Ah, I wouldn't worry about it too much. Trying to rig a fan up may end up a hassle in the long run.
If you're worried about overheating it and all you're doing is rock climbing, just richen your HSN and make sure you've got enough vent holes cut into your body. Shouldn't be a problem, really.
well so far it hasn been a prob....I'm not talkin about rock climbing...I'm takin bout runnin up a steep 25 ft. high sand hill......also it hasnt totally reach summer temps here in tx so i know ts gonna be alot hotter here....it was just a thought really......so far the temps are stayin between 210 and 230....