Yeah, that's possible. Blimps have been made with physics vehicles before. But never bot-vehicles.
If I figure out a nice way to make bot-vehicles fly; I'll consider this.
Play a bit with mass and/or drag, have a high airControl and i think
Support_HeightControl should work with bot vehicles.
EDIT: Quickly checked, i knew i left out some stuff by accident.
Anyhow, HeightControl is possible.
However, a client without Heightcontrol will not be able to go up.
This is something i will have to fix soon, i will push that fix together with the fix for something else that was needed so this is quite useful. :)
The other thing is too small of an addition alone to push out in my opinion.
Anyway, yes, Heightcontrol and a good airControl and mass and/or drag combination should work for a good blimp.