I like this. I especially like the idea of a flag. I don't know how many banners my men should get, and only mildly interested in finding out - my captain should know.
Costs will be based on your unit size, and will mostly be maintainance costs
Currently Scouts and healers are mostly maintenance costs, while the other paraphernalia are mostly an upfront cost. I think I like it that way. This is especially true for siege engines. If they become mostly maintenance, it will be difficult to carry them around when there is no siege planned; while it will still be difficult to buy them at the last minute. This could unbalance siege warfare.
