Many people install Linux-based distros on USB drives to use for, largely, basic PC troubleshooting. Has anyone tried installing such a thing on their Android phone's SD card? That way instead of carrying about both a USB drive and a phone, one could simply plug their phone in, boot the PC from USB, and set about performing whatever actions are necessary. Does anyone have any recommendations for particular flavors of Linux which are best suited to this task?
Amon Ra's recovery (Here for Dream/G1, see that post for links to other supported phones) allows mounting the SD card as USB Mass Storage.
ClockworkMod Recovery may also allow this, but I'm more familiar with Amon Ra's patches.
You could boot the phone into recovery, turn on USB-MS, and boot from your phone.
NOTE OF CAUTION: My Dream(G1) and Magic (MyTouch 3G) do NOT charge when booted into recovery. I don't know if I'd recommend this for that reason alone.
As far as I know, there is no Android device that can be put into a USB-mass-storage-thumbdrive-compliant mode (to use the nontechnical term). The phone would need to have a special mode where it emulated a USB drive and handled reads/writes to the SD card and that sort of thing. I can't imagine any manufacturer modifying the hardware and writing the software necessary to support this when the expected return on investment would probably be 0.