yes - it is possibe to achieve 3 x 1280x720 (16:9) on each output of a TH2G.
HOWEVER - it depends upon the graphics card as to whether it will.

I've managed this in a 2010 MacPro with an ATI X4870 card, connecting via the DVI-D port.

If the TH2G does not show this resolution in the MacOS - download the Matrox GMX Control Panel from the Matrox website - and you can program the device as required.

Let me know if you need further info

Simon


Simon