Man, the ultimate dream in my opinion would just be to get a standalone, runnable DOSbox environment with a rockin retro-looking keyboard on the bottom screen. But that's wishful thinking, hah. I know the DOSBox retroarch core is pretty alright, but I can still dream.
I personally love the quake port on the N3DS so much. It plays perfectly with the circle stick and it just feels so good. That bottom screen keyboard is also rad as hell. The Doom port is also hella awesome and the 3D is such a neat feature. I toggled the 3D on accidentally the first time I downloaded it on my O3DS and was like "DAMN DUDE!" I wish we could play Brutal Doom on the 3DS, but I know how hard that'd be to get running, since it requires GZdoom and everything.
But I seriously can't wait on Hexen II. I played a port on my PSP back in the days and loved it. Once that's up and running, all we'll need to complete the "class FPS" section is a port of ROTT!