I like the roll up doors too. I've been coveting them looking a fire trucks, which are almost always natural aluminum. Didn't know how much I like the painted ones, they really, really nice. I would think that rollup doors make much more sense than either top or bottom hinged.
Do you think they are going to seal really tight?
Started looking for 379 Peterbilt TC, 24' to 30' box, bumper pull--but ended up w/1999 Liberty Coach conversion of 45' Prevost XLV bus. 1,000sf heated/AC'd race shop w/dump station, 50amp shore pwr where bus parks, 3 NASCAR/ARCA race cars & 26' Bravo trailer.