Too late, I decided to visit this forum and search Feisty upgrade.. I had already started the upgrade process... Hey, I'm still a newb...
Anyway, I figured I was probably already pretty much screwed so when I was presented with the options of keeping any cfg files or replacing them, I chose to keep them. Then at the very end of the upgrade when prompted to remove obsolete programs, I chose to "skip" removing them. Rebooted, everything rebooted into Bianca, kept my taskbar, kept my settings. I use Mailwasher Pro and have it enabled during startup, it started but became very "ugly" again which is an Ubuntu trait. For some reason it looks good in Bianca though. The upgrade changed my repo's to feisty vs. edgy or mint but synaptic worked and the mint repos were still there along with 3rd. party repos which I re-enabled with no negative effects.
Bianca menu is still there and mostly functioning although the "system tools" button only shows Automatix now. The mint control center no longer works. It added desktop search to my taskbar along with the network connection icon. Added some additional fonts, kept my network connections including smb shares.
So in retrospect, not totally FUBAR, but the missing mint control center sucks.
I was just about to move to a larger HD for mint, so I guess this is a good time to re-install Bianca until Cassandra is released.