There is a link on this website for a version of libflashplayer that supposedly is flash 10.1

http://jacekowski.org/Maemo/Flash

the author got it from an IRC chat. He is the same guy that made the FMTX script for extra frequencies so I guess he is legit. He does not say if he tested it though.

I have tried it by replacing the original but when loading the about flash page from adobe I get a missing plug-in icon.
I don't know, maybe I did something wrong. I checked the permissions and changed ownership, but still it didn't work.

PS. the file size is around 8 MB as opposed to 6 MB for the stock one so it's shouldn't be a tweak flash version.