I would not stop just at completing LFS. You should create a more complete base system by completing Chapter 3 of BLFS, and adding any extra tools and libraries to handle various file systems.
After you finish making a good base, use
tar to create a back of the system.
Code:
cd /
tar cpfvz lfs-core-<date here>.tar.gz *
Next, extract it into /tmp and then work on getting things like fstab and any other settings for a temporary environment. Afterwards, check out AlienBOBs live disk for Slackware sources for any other ideas.