While the Jailbreak just changes mountpoints it should be possible to do the same for other places than the BDD, aswell.
For the JB, the drive is remounted @ HDD. So why not mount the dev_flash from USB?
Surely this is possible and I hope to see some action here soon!
So we would have a good solution to test and run custom firmwares as the brick risc is equal zero, because we can just unplug the USB device and the dev_flash is mounted as common - unchanged.