Mr. Anderson,

I agree that workouts shouldn't go much past an hour. However, part of the trick with GVT is to use shorter rest periods, since you're lifting less weight. You only do one exercise per body part... so maybe 2 exercises, or 20 sets per workout. I've actually cut the set count to 8 because of time before (I had to - I work out on my lunch break).
Here's a brief summary of the program:

www.leehayward.com/art24.htm

It's boring to do for very long, and I've never used it for more than 3 weeks in a row. But as a short duration muscle shocker, it's been quite effective for me.

-D