oh i would LOVE to do that... stock and BACKside... best of both worlds but I'm not smart enough to do it yet
you can run froyo and gingerbread together, but have to use a kernel that's made for the optimus s, zefie's xionia kernel is the only one I know of that works for both android versions.
drewwalton upgraded and fixed it, with his xionia redux kernel, but like I said, it's for the optimus s, so there's little tweaky issues using it on the v. like your home and menu keys getting swapped.
It's quite possible, though, and when I put up the port I'll include instructions and links for how to mix GB and Froyo, use just multiple Froyo roms, or multiple GB.
I've seen a few requests around the forums for multiboot on the V, looked into it myself a while back (
[DEV][Proof-of-Concept] Boot from SD on Optimus V - xda-developers) but it was too tweaky for the average joe to use.
Tasssadar's thing is just too smooth, and fairly user-friendly as long as you can use recovery and follow instructions.
When the port worked on the first try, I knew I'd have to share it for other geeky people like myself.
Serious nerdgasm with that touchscreen boot manager. That thing could fairly easily be built up to a whole little operating system, and I suspect it'll make it quite possible to dual boot a real debian install without android running at all. Lots more work to get that puppy going, though.