Regarding Global Market HQ - Instead of the traditional "click as fast as you can and still get left in the dust" interface, you should implement a bidding system. Players will put in bids for particular items (obviously a limitation on how many bids can be placed.) when a player 'advertises' an item, the system goes through the bids to find the oldest bid that meets the asking price. you would have to add in some controls such as bid time-outs, favoring higher bids in even of a tie, etc, limitations on how many times in a day you can place a bid for a certain item, etc.