Just for the info of anyone else in this predicament, I approached my local authorized Motorola repairer here in Melbourne. They wanted around $250 and their solution is to replace the entire motherboard. There was not an option for re-flashing the drive. I declined seeing as a refurb is considerably less.
I doubt they had JTAG facilities or the knowledge of how to use it if they did, they just replace the entire guts.
I have found plenty of places to fix an xBox, but not any to fix a Xoom. Sending it half way around the world, repairing it and sending it back will end up costing as much as getting a second hand one.
That is why they are called bricks. I will keep an eye out for a solution, but have little confidence. I should have been more careful. One lesson in flashing - follow the steps and not to rush.