Cortina Cycles/ CR1 Engineering built one up years ago at Sea Otter as well. en.wikipedia.org/wiki/Cortina_Cycles Although this one is more up to date and cleaner looking!
Entertaining but ultimatley a pretty big waste of some good components.imo.having rode a regular tandem,they're quite wierd,so having dh size tavel is a waste,cos this can't go too steep,on pure common sense grounds.I mean imagine the rear rider going over the bars on a technical steep part.that bike might be 14/15 feet long and that's how high off the ground the rear rider would be having went over the bars,so taking in the decent said rider would be on that would be a 20ft drop for no particular reason.Cool looking but just too impractical,i don't mind when i see them sep ut with xc kit on them.But dh tandems just do my head in,and i believe i'm in a majority.Just my opions though. The Gringo.