You could have
c: = ~/.wine/c_drive c:\My Documents\ = ~/Documents c:\Program Files\ = ~/Windows Progs d: = /mnt/cdrom
Then wiping your ~/.wine would preserve your files, and with those apps that don't require registry settings would just work without a reinstall (Pegasus Mail is a good example).
I think it would be better to figure out a way to do upgrades better. Also when we change something, it seems we need to massively increase the amount of time the old way is still valid for. The problem of being installing ancient distros then upgrading won't go away anytime soon.
