I would love to have a 2 seater (in tandem configuration) based on a slick velomobile like the Quest. But make it have full suspension, tilting in turns, and have either a small motorcycle engine and/or electric motor. Capable of running at least 55mph.
Closest thing I've seen is either the tri-hybrid stealth
The Tri-Hybrid Stealth
or the Raht Racer
https://www.kickstarter.com/projects...way-speed-bike