Mrs WMA - on the same search.
I currently have a Powerbag (
http://bit.ly/1o3Amns) which is heavy and sort of saggy (it tends to fall away from the wheels if I have it front loaded.)
Started to look for a roller bag that could fit in the United "Personal Item" sizer as I always travel with my "rolling briefcase" as well as a domestic carryon roller. But absolutely NOTHING will fit the personal sizer AND have wheels (that I've found).
No way I'll spend the Tumi Alpha Wheeled Briefcase kind of coin (the Powerbag was a daily deal purchase from somewhere).
Good luck and I'll be watching this thread with interest.