That's actually really cool, cheers!
I've got some ideas and feedback here, sorry guys but I'm back with another wall of text.
Starfleet usually put the nacelles away from the habitable areas because they emit dangerous radiation. Still, something similar to your proposal is possible... If the nacelles were put back and to the side a wee bit more so the saucer, erm... Orb volume wasn't suffering so much from radiation.
Edit: Added sub-headings to organize ideas
Archer v2:
So I'm rereading the Archer-class threadmarks. Looks like we got a choice for a secondary hull deflector that would've also meant increasing the ship's mass and thus cost. There are ways to mitigate the cost, like light shielding, but I digress... We could make that work and increase internal volume even higher by using 1 of those white cylinders as an engineering area, raising or lowering it a bit so the deflector can peek out, widening it. It could easily contain a large amount of shuttlecraft and workbees, and tons of machine/repair shops, could be a +8 - +12 engineering module right there before we even get to the orb. Then the other white cylinder could be a detachable cargo pod.
Of course both cones could be used for detachable cargo pods with an inline deflector and the warp core entirely within the sphere, so long as there's a reasonably wide space between the cargo pods for the nacelles to see each other. That'd double the carrying capacity of the Archer v1, extremely valuable if we consider this hypothetical Archer v2 would have a warp 8 drive and possible be late enough to have v4 nacelles with higher cruise speeds.
Archer large cargo:
Another alternative branching off from that idea, is to have 1 white cylinder being an engineering hull as before, the other being a
large cargo pod, which my math shows as ~120 kilotons of cargo as opposed to 30 kilotons. That'd drop its speeds by a whole warp factor, but that's large enough that Starfleet could use such a ship in its core and middle territories to transport virtually all the required materials to build an entire starship, outpost etc with a single transport. Assuming it's only transporting stuff like phaser emitters, warp coils or other highly technical, critical supplies that benefit could be staggering. With its speeds still being substantially better than civilian transports and a smidge higher than the Archer v1, the benefit of that speed and capacity is amplified further, since that's potentially doing something like transporting the warp coils for 2 entire sets of nacelles (not counting any interior cargo spaces, could easily be a half-dozen phaser emitters and a couple torpedo launchers etc stored internally) and them arriving in 2 months instead of 6, drastically increasing our military industrial efficiency.
Edit 2:
(The Archer-class has an efficient cruise of warp 5.2 and maximum cruise of warp 6.2. If we take the canon Constitution-class as a conservative estimate of a warp 8 drive as opposed to ours, that yields efficient/max cruiser/sprint of warp 6.6/7/7.8. If we assume we take a -1 to all warp factors due to the large container, then we're looking at warp 5.6/6/6.8. Too slow to be tactically useful for retreat/evasion, but still faster than the original Archer-class in efficient cruise and slightly slower at max cruise.
I believe our warp drive/nacelles are optimized for higher speed for greater cost, so our hypothetical "Archer large cargo" probably is +0.2 warp factors higher overall, making it just as fast when time is critical on deliveries, and +0.6 factors faster when it's cruising in economy mode, meaning further advantages in operational range and day-to-day efficiency. Corrections from others gratefully appreciated, I don't have time to deep dive any more into this Quest's mechanics right now.
Remember it's transporting more than 3x the cargo, and would benefit from enhanced tactical systems (covariant or type 2 shields, possibly v4 thrusters and possible improvements in near-future armaments) making it less helpless, and a greater willingness for Starfleet to actually deploy them, and if it's that useful can be retrofitted with the warp 9 drive and v4 nacelles, vastly increasing its lifespan and utility and saving us critical $$$ and time.)
Archer Q-ship:
If we go with a couple fore and aft photorps, light covariant shields (remember the amount of shielding scales with size, if it's a chunky ship that's actually quite a lot of shielding) and maybe give it a couple thrusters (or v4 thrusters, we actually debuted the
experimental v3 thrusters on the Archer and they paid off and then some) and some better phaser spreads, that means it'd be non-trivial for an enemy to disrupt our supply lines. It starts getting to the point that a few Archer v2s traveling in convoy could take on
cruisers without any escorts, and such a ship sitting over one of our colonies etc could actually be a deterrent against light threats like raiders or at least single current-gen BoPs, without requiring dedicated and extremely expensive escort ships.
Edit 3: Of course, we could accept that even an orb-ship must be
able to fight and give it fore and aft RFLs. Combined with the latest shielding and other battle technologies, it might be enough to keep casual raiders and pirates away from core facilities where these will be deployed in larger numbers, thus decreasing the number of ships needed to provide internal patrols, and perhaps also providing a final reserve of martial strength in dire situations.
Science Orb:
Either way we'd still have the space inside the orb for a huge cargo area and/or massive machine shops, enlarged crew quarters. Other possibilities were brought up when we were designing the Archer, including geology and geophysics labs, general science labs, a triage deck etc. I'm opposed to those options, but they're there, and I could easily be wrong about their utility and they could be a great boon.
Another alternative occurs; instead of a transport ship,
a mass-science ship. We could find out whether or not it's possible for
Commotion$ocks' idea for habitation areas to actually happen (radiation concerns may be moot by distance from nacelles) and thus vastly increase the module space within the orb. Or, if not possible, use those spaces for engineering hull and extra utility/science modules. Then we could have a general science ship with a
vast number of labs to service our colonies, including geophysics, pharmacology, general science and
Colonial Support Orb:
possibly the long-desired triage deck, and still have enough space for a large extra module, like huge cargo bays or machine shops to provide supplemental colony or emergency ship assistance. It could service all of our mid and outer-rim colony's scientific needs, providing plague relief, keeping our vaccinations up-to-date against any emerging bio-threats and emergency support while also providing a helping hand upgrading or setting up facilities on fledgling colonies.
Could also use a module to add extra range so it can putter around our colonies for months or years between refueling cycles.
Sorry for wall of text, hope some smarter and wiser brains get some inspiration, or at the very least someone gets some enjoyment.
Thanks again for the time you spent on those images, really got my brain spinning and spitting out ideas!