For those of you towing TT's or FW's with high door thresholds, you may want to check into these scissor steps that replace your slide/fold out steps:
http://www.torklift.com/index.php/products/steps-handrails/glowstep-revolutionAfter going from a high sitting high profile bumper pull toy hauler to a low slung enclosed trailer and feeling the difference in handling, I question cranking anything higher that already starts with a high profile. With many of the FW's already approaching 13.5' overall height, I would also be looking at what your actual height is now with modifications. I always forget that GM's sit lower than the other two brands, so maybe that much lift is not that extreme.