I have a further suggestion, regarding people wanting (no DEMANDING) the convenience of buying things from the item search window. This really seems to be the biggest sticking point for people, and when they cry "give me mai AH!", this is what they really mean. The don't mean a true auction house, with any sort of bidding system. They want to sit in one place and buy stuff without having to move their butt off the couch.

Well, I suggest that we give it to them. (I know I'm not the first to suggest this).

Allow players to purchase items from the item search window -- but make the pay more for the convenience. The current tax rate is 10% when not in the market wards. So, simply add an option to the search window for "delivery" to the players retainer. The delivery charge is 15%, so the buyer pays 15% more then the listed price, and the seller pays tax as is usual based on what ward the retainer is in.

This is roughly in-line with the charge to have a pizza delivered to your home, or the recommended amount to tip in a restaurant (at least where I live).

If a player INSISTS on having the item delivered directly to him, where he is standing? (Well, no MMO I've ever played has done that ... the items have always gone into the mail, and have to be picked up from a mailbox). Well, for that exorbitant feature charge a 100% delivery charge. Yes, the buyer could pay DOUBLE the price to have the item delivered to him in person. Kind of like how much a tow truck charges to come and fix / tow your car if you break down on the side of the road.

Even with these exorbitant fees, I still worry that with all the gil in the economy currently, even these fees wouldn't be enough to keep botters from controlling commodity markets. But, it would put up a barrier to make them less competitive.