@Stuart Briscar is right: RangeMe handles this function well. Its parent company, ECRM, also hosts what they call EPPS (Efficient Program Planning Sessions) trade shows, but which are really speed dating sessions with retail buyers.

There have been some others who have tried similar concepts, but the big impediment for a new player is getting a large enough audience on both the buying and selling sides. ECRM has been doing this long enough that they have a significant head start in amassing an audience.