From the specs of the MXO it should work. They do advertise it as broadcast quality dektop presentation output.
I had no chance to check the quality of the HD-SDI - but I could connect it to the input of the blackmagic extreme and see what happens...
Has anyone expierence with HD-Live input into catalyst?

I believe the main issue with any capture and playback solution is that some kind of scaling will appear and you will use your pixel accuracy.
When I think of most of the powerpoint presentation I have seen so far - I doubt that a 6 point font would still be readable after scaling it up or down a little...

I will keep you up to date with whatever I find out...