I was going to order a SD/FF from Eyetech but I mailed them to ask about the stock levels and if there were any issues with fitting one to a 1200 with a FASTATA (I heard there was).
They mailed me back....YES we have them in stock (fantastic) and YES you can't fit one with a FASTATA.......damn!
I'm still looking for an alternative, the external ones go for silly money on ebay, and I’m just not prepared to pay £150+ for one.