I've discovered that a microwave oven transformer can have it's high voltage frame connection (why do they ground the high voltage to the transformer frame?) insulated quite easily.
When I then feed 240V mains into that coil, the original primary gives me 26V on the transformer I tested.
The wire used on this transformer looks like it would easily cope with 10 Amps or more.
Would this be a suitable and safe starting point for a ~32-36V powersupply for stepper motors?
These transformers are easy to get - they seem to survive the demise of the microwave tube thingy...