After reading this rather lengthy debate of rappel vs. BASE jump I just had to register and weigh in. For the ultimate highrise escape rig checkout
www.gekkomat.de It's a little pricey and a tad bulky to stick under the desk but it seems like the best hypothetical solution to me. Besides, I wouldn't have the guts to swan dive off the roof and I wouldn't trust those without a swiss seat to not cut my line <img src="images/graemlins/smirk.gif" alt="" />