I would absolutely love to have 720p GTA III on the XBOX as it has the best models of any versions. Also would I need extra ram in order to run games at a higher resolution?
Yes there is a way to do it, but there are often some odd issues that can happen as a result. Offset UI, slowdown, glitching, etc. Some games run perfectly, others dont. Just depends on the game. I feel a CPU and RAM mod would be beneficial but I can't honestly say this as a certainty. For example Jet Set Radio Future can be put into 720p mode, but the slowdown is so intense that it's unplayable even on a RAM and CPU upgraded suste,(unless youre a very very patient person).
I believe OP is asking about what to do and how to do it on the software side as well, I'm actually interested in that as I wouldn't mind patching a few games to run in HD.
On the PS2 side of things I usually use GSModeSelector but that sounds pretty cool, I'll check it out!
There was some tool I saw a while back on the ISOZone forums but I can't seem to find it for the life of me. It was able to patch many games iirc but it had some pretty bad flaws.
Anyone have luck patched Halo 1 for 720p? I followed the instructions on PS2wide and tried OgXHD but the game still boots in 480i. Trying to launch from unleashx and xbmc which are set to display in 720p.