Boot from USB or alternative? V90LE

Boot from USB or alternative? V90LE

I am hoping to boot from USB on the metric boatload of v90le's that I have.
Short version. I want to boot portable linux desktops straight from USB that users can take with them. I of course already have the bootable USB key worked out, just not how to get the v90le to actually start from the key, instead of the flash on board. PXE is of course available, but not viable as a permanent solution for me. 

So the options I see...
Actually figure out the magic voodoo required to boot from USB. (be it keystroke or new embedded image).
install a new image that will be barebones "something" that will then allow booting from USB.
or the worst case, run a virtualbox/vmware instance inside a stripped down XP/linux embedded image.

Any hints at all, or even alternatives would be greatly appreciated.

sidenote: I also have a ton of v10L boxes which would be great to run the same as well, but lower processor and ram put it in the "spare time list" instead of mission list.