Out Of The Cradle (a site that I've also added to the space blogroll) has an interview with David Livingston, in which he decribes how he almost didn't do his dissertation on space tourism, and how The Space Show got started.

They also have the first part of an interview with John Powell, of JP Aerospace.

I visited the JP Aerospace web site and read about the proposed Airship To Orbit. Why do people interview these nuts (John Powell) and not point out that their ideas won’t work? If you know anything about L/D, fluid dynamics, non continuum fluid dynamics, drag, and state of the art electric propulsion you can find the fatal flaws in his plan on the back of an envelope. I didn’t catch what his educational background was, so maybe he’s not a nut, just uneducated, but my first question remains.

Actually, as far as I know, he's been too secretive about how exactly it works to determine if there is a flaw in the plan, or what it might be. It's certainly appropriate to be skeptical, though, until we get more information.

He’s counting a combination of aerodynamic lift and buoyancy to “fly” above 200,000ft. You can assume any reasonable L/D you want, then compare the drag to the likely thrust of electric propulsion and find that he’s at least 2 orders of magnitude short. There are other problems not the least of which is power for the EP. This is a simple problem that could be worked to fairly high precision on a spread sheet. I just assumed some averages and found that it’s not possible. Maybe I’ll do the “exact” solution tonight if I have time.