An idea that would go along with your public idea could be to post a trade 1 week before it is due to happen and then if anyone will do a better price they can bid it up or something?
I for one really like the idea of themed troops that you would sell. Even if the gear isn't totally loomed, people may still buy full armies (from an RP perspective that would be awesome).
This was Kinda my idea:
Something similar to that. I'd put the bidding up for 1.5 weeks with a minimum bid(the 50g per troop price maybe a bit cheaper). So what I would do would post troop amount and gear. You then send me a bid via PM. The Bid won't be posted so people have to guess what to pay. This way it's a gamble. Put down 500k and be only bidder or put down 50k and be one of many. You could change your bid during this time frame up until I close it(as It'd be via PM/other private methods, timestamps will show bid times). Highest bidder wins and gets announced(?)
The next way is to put max mid and change it, but that shows the bidders who's winning and with what amount and I'd like to make it fair game.(of course factions with more money have the advantage, but how many times?)
I actually within the next 5 days should have enough to do another decent size trade. Perhaps I'll put it into place then and see the response then?