I'm sorry 60 inches, 5ft...thanx migreendo you mean 60 feet or inches, or 6 feet?
with 36x30x60" you only have 37.5 cubic feet, so you shouldn't need anything bigger than a 4" fan which clears 175ish CFM (cubic feet/minute.) according to jorge, you want to be able to clear all the air from your room within 5 minutes. as far as intake, i agree with the passive system...it's what i'm working on now, myselfeasy... use a passive intake, get yourself a 400CFM inline fan and a fan controller, an air cooled hood or cooltube, a carbon filter for smell, and that's that.