but with a long bb you have the piece of mind that your frame is not going to get dug into by chainring teeth anytime you do a sideways hop. with a shorter bb, you might not be able to transfer it across from one frame to another (Y)
i have a 128mm truvativ giga pipe DH, its truely beasty! it aint gunna snap in a while, i would suggest getting one : http://www.chainreactioncycles.com/Models.aspx?ModelID=4981
but if tartybikes have any, then get them there :)
Ta
Will