Ugh, this sounds MIGHTY tempting... but I got so many apps installed and customized.... xD
I'm aware that there are some "backup" programs for jailbroken stuff, but are they reliable? I have heard horror stories where the restore process is borked.
I just used PkgBackup to restore 4.1 on my iPhone 4 yesterday. Went as smooth as silk. What I've found is that as long as your are moving from one sub-release (4.x to 4.x) it works great. Jumping from 3.x to 4.x for example just introduces too many variables of change.