1. I bought mine from green-sum on Ebay, no problems and his feedback is pretty spotless.
2. the Catleap range takes Dual-link DVI, which requires the powered adapter for (I use Apple's one for the MBP, and bought an extra minidisplayport -> displayport adapter for my work laptop).
I bought Apple's dual link adapter (http://store.apple.com/au/product/MB571Z/A/mini-displayport-...) . Was on special at a local store. It's not without problems, particularly awaking from sleep sometimes leading to "static" image blur requiring reconnection of the adapter.
When that happens, you can just put the display to sleep instead, then wake it a second later. That fixes the problem for me at least. The standard keyboard shortcut to put all displays to sleep is Shift-Control-Media Eject (⏏)
Odd, I bought the dual-link adapter from monoprice and I thought I got gypped when my wife's Yamakasi Catleap would wake from sleep that way. I guess mini-displayport is just flaky in general.
That will not work. You, unfortunately, need the expensive USB powered/assisted adapter. (I have both. Had to buy the other to drive the high resolution.)
2. the Catleap range takes Dual-link DVI, which requires the powered adapter for (I use Apple's one for the MBP, and bought an extra minidisplayport -> displayport adapter for my work laptop).