Don't know about a 10G thumb but I have a portable HD thats 250G and its smaller than a checkbook. Their going for around $100 these days. I carry it instead of my Thumb most of the time now, same concept only a bit bigger and ALOT more storage.
I have a Western Digital like that, it's been fantastic.
"The inherent vice of capitalism is the unequal sharing of blessings; the inherent virtue of socialism is the equal sharing of miseries." - Winston Churchill