You could probably get more response over on the HTCP Mac area of the forums.
But I'll tell you that I've just hooked up this last week a Vizio 42" plasma to my PB G4 and it works fantastic. So a much faster Mac Mini should be perfect.
Hooking up from DVI>HDMI is how I have it as well. You'll just need to use SwitchRez to set your sets resolution on the mac and have it work.
Hope this helps.