Well, not long after inquiring about WiFi earlier in this thread, I ran across the news posted yesterday at PS2Dev:
http://ps2dev.org/
It sounds like the WiFi stuff is being worked on, so that's good. There's also work going on for an implementation of OpenGL for the PSP, which is something you also think about when discussing Quake ports. I can't tell if this is something that could be applied to Quake ports, or just new homebrew graphics engines, but regardless it's welcome news.