I've just been looking for the same thing and www.trackitdown.com is the best I found at the moment. Not the same size library as a regular vinyl site but its getting there. I get the impression they are expanding daily.

I can't ****ing wait till we fully go the way of paying a buck or 2 and download the tracks (and every club has final scratch or equivalent as standard equipment). Everyone is afraid of the mp3 thing.. but I think the opposite. I think sales will be up and exposure across the board will be greatly improved. Instead of spending 50 bucks on 5 records (plus awful shipping).. I'll drop $25 on 12-15 tracks. At the end of the day, I've supported more artists and the actually money that gets to each artist is similar when you think about how much of that 10 bucks per record goes to all the red tape involved in vinyl. (pressing, distro, artwork........)….

Who knows how much you profit per sale on a vinyl release? Can’t be more than a buck or 2.