I have a TripleHead2Go that I use with my MacBook Pro 15" Santa Rosa machine. It's running at 3840x1024 resolution and working great. I'm running Mac OS 10.5.8 and have version 1.01.00.005 of the control panel software installed.
My TripleHead2Go has a USB port for power and communicating with the control panel. I normally power the box with an external USB power adapter, but if I want to use the control panel, then I have to plug the USB plug directly into my machine. If it's plugged into an external power adapter the display still works great as long as it's pre-configured correctly, but the Matrox software doesn't detect device or allow me to change any settings in the control panel.