On the wiki link I posted the other day of open-source games I came across PlaneShift so installed it on my mac here.
Its a MMORPG, the graphics on full detail are quite impressive and shaders can be turned on or off (interestingly they are off by default). When you have time kas1e can you take a look have a see if it can be ported?
If i remember right, etherland use shaders. I can't be sure 100%, but as far as i remember, deadwood start to works on mesa for aros because of that game (i.e. other implementation was not solution, only full mesa). What make me think that is shaders based.
But, you can check it yourself on site use it shaders or not, and if not, we can try to port it as well.
There has been a great point and click game set in a future world. It was a game from the years 95+, one of the last Amiga games ever made. I do not remember the title unfortunately not the developer.
What about, Shank, Dirt 3, Black Ops, Mafia II, James Bond 007: Blood Stone, Lost Planet 2, Fallout: New Vegas, Star Wars: The Force Unleashed II, just to name a few, lol.
Seriously, until we have the adequate raw power and the technological standards, porting good games is a no - go. Even indie games or games from small companies, require all the things we miss: All games from Amanita Design http://www.amanita-design.net/ , are awesome, Shank can blow your mind as one of the best beat 'em up, Trine, new Alien Breed series, Danger Balls, World of Goo.
Free or opensourced ? Free game are not open-sourced by default. As i can see its just free (without sources), and if i am right there, you can try to contact with authors of the game, and ask for sources , and we can try to port it.
Anyway, I have most of the open source in my game's collection. 9/10 are crap some are good. I believe that the above list should cover many genres. If they are portable I don't know.
Its that game with the dodgy graphics at the top of this page, hardly worth porting unless Afxgroup plans to redraw the graphics and re-code the engine lol
In that screenshot why is Spock (a vulcan) in a medieval setting sat in the grass doing yoda? Whats it all about? :S