Well, up a hill and starting from a stop is where an unassisted velomobile has the most trouble. And, most of them are Dutch designs, where hills are a non-issue, so weight is often treated as a non-concern - we're talking in the 70 pound area unladen. Assist just makes that worse.

Mind you, Trisled managed to get one under 41 lbs, and that's with a CrMo frame and CF shell. (Meanwhile, a Carbon Quest, which is CF monocoque, is like 65 lbs.) I've got some ideas for one using a CrMo frame and a hybrid dacron/coroplast shell, with target weight under 50 lbs.

In any case, once you get it rolling, and you're on level ground or downhill, things really get moving.