SpaceBass,
You're in luck.
Radiocycle, the NW moderator had the same question about replacing his old TravelPro bag... this thread is here:
http://www.flyertalk.com/forum/Forum35/HTML/006494.html
It's actually very informative and the PurdyNeat bags they speak of are actually very good for frequent travel.
You should try e-mailing a few of the posters to get a personal response on those bags.
Hope this helps.
aloha