New Business Card Rescue CDs
Linuxcare has introduced version 1.2 of their business card-sized rescue disks, which now contain 140 MB of recovery tools, Debian install capabilities, the X Window System, PCMCIA support, and ssh. From the picture they look pretty cool, too. I remember seeing the business card CDs at a COMDEX a couple of years ago, but this is easily the best use I've seen for them, and is a needed improvement over the previous version.
http://www.octave.com/551519/en/cdrmedia/businessc ard.html
One problem I had with the CD is that its size and shape makes it prone to "falling through the drive tray" when I use it in one of my SCSI CD-ROM drives. It's just small enough to slide through the slot in the back of the tray if the CD stops spinning at just the right position.
I've been carrying the CD around in my bookbag and using it on campus lab machines. When I need to ssh somewhere, I reboot the machine with the LinuxCare CD in it, run dhcpcd, run the ssh installation script (which pulls a .deb of ssh from a foreign server and installs it on the ramdrive), and ssh as usual.
As for availability, I doubt you'll find these things outside of computer shows. (Why not start a project to create a similar recovery CD?) As for its shape, look at www.shapecd.com for all the weird shapes you can have CDs cut. As for size, it's only slightly taller than a business card but not as wide.