I made a post somewhere here on dual booting and how it could be done.. backing up and restoring automated can easily be done, even with a script, but very slow process. I was trying an approach kind of how the app 'boot manager' works, but was trying to do the things it does manually as it can't access our boot.img while phone is running in AndroidOS. Our boot manager is accessed by recovery mode and download mode only.

I tried a few things, failed, didn't really do much debugging with it, just doing things based on my theory. Check out http://androidforums.com/triumph-all-things-root/578310-dual-boot.html

Maybe I will go back to some of my theories on dual booting and try them and actually debug them and see what kind of errors I am getting instead of just trying another method each time.

I forget who it was but someone posted a link on that thread about the Optimus V having a dual boot, but it used same kernel so you had to use 2 roms that were compatible with same kernel.. I just seen you had Optimus V on your device list.. thought you may want to take a look at that.