Bruce, this looks like a good place to start a scratch build. What do you think of the power and run time? I think it should run all-out for four minutes. I'm working on a stik based around this setup. (hey, that's what stiks are for, right? Shop hacks!)
Oops, forgot the link!
http://www2.towerhobbies.com/cgi-bin...?&I=LXFAH8&P=0