Re: T-Resc on USB

> Not too many BIOS boot from USB HDs.

Wrong.  In the Wintel-PC world of today, most BIOSes are Award Phoenix
or somesuch.  There are but a handful of BIOS vendors and they've
handled USB for years.  Yaboot on PowerPC can also do it.  More obscure
architectures, I don't know.

Lacking BIOS support, you can use kexec from CD to switch kernel/systems
to USB, like chroot but actually switching kernels.  Google for docs.

Another interesting link,
http://advancemame.sourceforge.net/boot-readme.html

If you are not developing T2, but just want a rescue system on USB
"right now" without fiddling around, grml.org is an excellent choice. 
Depending on drive size you want grml2hd (for USB > 2 gig or so) or
grml2usb (for smaller USB devices or anything flash).