Uhaul has an interactive website I see. They won't rent me one if I'm pulling my S-10 with an S-10. So I guess thats out. From what I can tell, this is also true if I want to use a vehicle trailer. I don't guess its necessarily illegal, but I would guess their engineers are covering their ass from possible lawsuits.
oh, and I have a tough time getting my tcase into 4lo on purpose!