***stripped down version of Feather Linux which is a stripped down version of Knoppix.***
these distros keep getting smaller and smaller
1. External HDD. You will need of course usbcore, the, possibly, EHCI, OHCI, UHCI, the external USB disk drivers to work...
2. The problem with stripped down versions of stripped down other versions is not always having what you want in those version.
I still think knoppix is worth a try.