In 3 or 4 years of messing with these switches I've never seen any on ebay, I would imagine you'd have to find a vendor with some old stock left ovet to buy oneAnyone managed to pick up any of the DC PSUs for the 6610? They're RPS16DC-{I,E}.
make sure you have a -48V power supply (eg the + rail is tied to ground/earth). If you plug in a normal power supply (eg negative is referenced to ground/earth) it'll fry both the switch and the power supply