Originally Posted by wheelspeed

All valid comments. To muddy your thoughts further... a tandem puchase doesn't have to be a 'business' decision. Some of the fun of riding a tandem is that it always invites friendly conversation. If you're planning to do social rides and other non-competitive events with your wife, then it may be fun to have an unusual tandem that represents a past trend. Especially the older ideas that worked pretty well but didn't survive because of outside reasons. If you love the way the bike rides, and think that you'd keep it a long time, then you may one day have pride in showing off a well-maintained tandem with an unusual design.

I took a quick look and it appears that many parts and also entire kits can still be found. You could get parts now and just keep them somewhere.