Optimal Linux Distro to Install to SD card to use as USB-Bootloader for PC?
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.