I wouldn't even know where to begin, at least on the mundane material side of the equation.
As for enchanting materials, I can help there.
Each Legion is to be equipped with a
Lord's Banner of Swiftness (1,000 IM to enchant or 2,000 to commission),
Lord's Banner of Victory (7,500 IM to enchant or 15,000 to commission), a Whispering Brazier (810 IM to enchant; we should consider equipping each Legion with at least one spare, considering the price and importance of these), and Gemstone Table Anchors (6,992 IM to enchant a set of Anchors for one Legion).
Our first 10 Legions already have Banners of Swiftness and Victory, and we commissioned 10 more of them last month, which will allow us to cover all current Legions plus the next several that are formed. There are currently Gemstone Table Anchors for the first 8 Legions, with 10 more sets of them already on the crafting schedule for this month.
After all of these are assigned to their respective Legions, equipping new ones (assuming we do all the enchanting in house and give them 2 Whispering Braziers) would cost 17,112 IM.
We are also working to craft more of the Valyrian Steel PfE banners. We currently have 9 of them with 8 more on the crafting schedule, so enough for each Legion to have one, along with a couple spares. Each of those protect up to 1,024 people from mind control, but cost 20,480 IM each, so while being very important to have as many of them as possible, they're not something we can reasonably afford to produce in sufficient quantity to protect every soldier in each Legion. That said, I would like for us to be able to equip each Legion with at least two of these banners, at a cost of 40,960 IM.
Something I think we should consider adding to each Legion, and which wouldn't cost very much but should make logistics and field deployment simpler while improving the basic quality of life for Legion soldiers, is a set of 20 Rings of Prestidigitation and Rings of Mending. 20 of each ring would only cost 1,800 IM, or 3,600 IM in total, but they would be very helpful in promoting basic hygiene, keeping materials clean and ready for use, flavoring meals to promote morale, repairing minor wear and tear, etc.
All of these taken together, including the 2 PfE banners, totals up to 61,672 IM per Legion.