Bike Hugger 

I used to work at a bike store in Hawaii that had one of these frames for sale. It had a little storage compartment on the side. When you opened it, you could see some of the internal bracing.

I don’t think it ever sold.

Ah, so it’s not just a plastic box hung on the top tube?

this was tri-geek chic, c. late 1980s.  Trimble also made an mtb which was had a single massive “boom” tube instead of top and down tube.  i’ve seen one in person, but i can’t remember if it had separate seat/chain stays.  this is back when Kestrel was big and “composites” were super exotic.

Klein was doing OS, thin-walled aluminum tubing too?