Hi team,
... and it's not a brand-new idea. S' ahead (I'm a genious ! 1st. on my google search):
http://www.ibm.com/developerworks/linux/library/l-fireboot.html
Why it interests me ? because I'm stuck with one old PC with a loose USB and probably others too in a stormy night & no lab open. I bought an adopter USB-female to firewire-male. I didn't succeed much. I also tried an adopter to the green round socket of the mouse. NADA.
But I hope SB will take it ahead. I think it's a MUST-HAVE-IT to my Potchan (=opener).
Potchan 
That looks like booting a 'small' Linux Kernel first, after it comes the rest of the OS from the Firewire device.
Will it be possible to load a part of the Linux Kernel, until it detects firewire/usb storage devices, than chainload a MBR sector from the storage devices?
There is somekind of fast-reboot mechanism for Linux with going through BIOS again, but I doubt it can be made to jump to MBR again.