seems like an opportunity for automation. I bet you could do something where you slurp down a csv of your credit card transactions (most banks let you do this) and then go through the merchant IDs to figure out who to send the 1099 to. Now, sure, going from the merchant ID to a tax id and address for a 1099 would be quite a lot of work, but that's where the central service comes in. You could either sell the credit card id-> tax id database, or you could 'crowdsource' it- (though you would have to solve a major trust problem) when one user of your service figured out the tax id mapping they would share it with the others.
