I have a tc electronics Vintage Delay pedal which has a pretty small power supply. It uses 12 V dc and the power supply is rated at 1.25 A (1250 mA). It is a switching power supply like the Diago, so you can use it almost anywhere in the world (110-240 V). TC provides adapters which can be easily changed to make it suitable for the most common wall outlets (US, GB, Europe).
I don't know if it's technically possible, but it would be a great idea to try and use this kind of design for the Eventide factor psu. The supplied current in the TC psu is even higher (by 50 mA), let alone the voltage. There should be a way to do this. Or am I missing something completely?