LifeBoat
"LifeBoat is a script program which can be used to create a Linux bootable rescue CD. [...] The LifeBoat rescue CD only uses memory. After you boot LifeBoat you can remove the CD and use your CD-ROM for other things such as mounting your backup CDs. You do not need working hard drives or clean file systems to run LifeBoat. You can repair your corrupt file systems from memory based LifeBoat.
LifeBoat has no security. It can be used to repair a broken or forgotten root password. LifeBoat builds a rescue CD by copying some your Linux system components to a CD and making the CD bootable. [...]
LifeBoat can be configured to your needs by adding utilities you need for your system. LifeBoat has an Addons function which you can use to add utilities which inspect and repair components specific to your system, such as RAID or a journaling file system.
LifeBoat will create either a CD-R or a CD-RW at whatever speed you choose.
Once you get LifeBoat configured to your system you can easily burn a new LifeBoat rescue CD. Whenever you make major changes to your Linux system you can quickly burn a new LifeBoat CD to match your latest system."
http://users.rcn.com/srstites/LifeBoat/LifeBoat.home.page.html