Well, according to the OvergrowFAQ, it is possible. A little complicated, but possible...and if it works like it's supposed to, it might be very effective and stealth...

IMO, I would not risk it. Too many things can go wrong. I agree with The Yeag. I would spend your energy (and $) trying to develop a good neg-pressure system with a nice carbon scrubber.

G'luck.

TGF