I phoned musical fidelity today and spoke with a very helpful technician regarding the discontinued X-PSU power supply.
He told me that the X-PSU was nothing more than a 105VA toroidal transformer with 4 outputs @ 20VA each.
All the smoothing and filtering etc takes place on board each of the X-ponents and NOT in the X-PSU.
He explained that the upper PCB in the X-cans V2 dealt with the power supply end of things.
I asked him what he considered was a suitable transformer to use to power an X-can and he advised on a good quality toroidal... anything from 20VA up to 500Va with an output of 12V AC (the higher the VA the better the regulation) he reckoned best sound quality would be acheived with a transformer that acheived between 4 and 16% regulation.
I've been looking around and a 1000Va toroidal is rated at 4% typical regulation so may well try one of these in addition to the 50VA I am working on at the moment which has 14% typical regulation.
For pictures of the power supply circuit in the X-Cans have a look at a couple of examples I have just uploaded to my website.. I'll upload all the details of the power supply I am working on by this time next week and will report on the sonic changes (if any) to the X-Can.