Mobile Hard Drive compatible with WFT-E2/WFT-E2a

[DAP]

The EOS WFT-E2 comes packaged with a nifty black case suitable (so says the instruction guide) for a pocket/mobile hard drive.

I was wondering if anyone has found such a drive which is compatible with the WFT-E2 unit in that it can be powered from the USB port on the wireless file transmitter WITHOUT need for an external power adapter.

I have read, in several places, of people who have purchased mobile hard drives, only to find that while the drives are designed to be powered from a USB connection, the particular USB port on the WFT-E2 does not provide enough power to permit proper operation of the drive in question.

If a fully compatible (known to be operable without external power) does exist, I would be grateful to know the make and model.

DAP