You didn't mention the size or frame material, but if I had to guess, this may be one of the aluminum Scott-branded ATB tandem frames sold by Chucks Bikes a few years back. The frame was your basic off-shore, batch production model: nothing special, but nothing awful either. Just a generic tandem frame modeled after the Cannondale frame geometry. I believe they offered the frame & fork for about $250 and, again, the quality was stellar but close enough to make for a good frame to go bashing around in the woods or to cruise the local bike path.
However, I seem to recall that there were a few higher pedigree Scott tandem frames produced back in the 90's, but there were only a handful and they may have been promotional one-offs, similar to some of the GT full-suspension tandems. In fact, the first Ventana full-suspension tandem was a marketing tool created by Gibson & Turner for Interbike to demonstrate the robustness of the MFS rear suspension system used on the Ventana Marble Peak. Gibson went on to race the thing and son-of-a-*** if they didn't start to get orders for the bike.