I can probably write that actually lol. All that sounds like is needed is a bot to look through every new post body for a certain keyword or phrase then resteem that post to the steem-store and comment on that post the user names and post links of everyone who has expressed interest in such an item? Would the bot handle the financial transactions also? that might take a little more work and require users to trust you with their active keys... but still doable. . Do you know in exactly what manner you want this bot the behave? Or should I just start writing one and tweak it later as you see fit?