Here's some info I found on the Ubuntu wiki:
https://help.ubuntu.com/community/LiveC ... romScratch
I don't know if you read that before but it could help you understand the liveCD generation better and maybe give you missing pieces in the puzzle for remastersys.
I'm hoping to tweak reconstructor so I can generate my initrd/casper directly from my chroot env... maybe this is going to help.
Anyway, it's an interesting read.