personally no, i dont htink they will.though next gen is far superior its just not THAT superior to the point where they can emulate other consoles. i mean there is a new snes emu out there now that emulates a snes EXACTLY the way the system is. and a 3.2 p4 cant run everything 100%, on a more realistic sale, n64 emulation on pc aint perfect yet so on next gen machines its not likely. dont get me wrog though, what you see with the xbox 360 and the PS3 is a limited PC, with a few minor differences. looking at the xbox the current gen are barely 5 times more powerful, when i think i read somewhere they need to me 50 times more powerful or 500 times, but you can see that emulating these consoles are a long way away, though DC has improved and is running at 10fps to 20fps, where as ps2 has reached only 5fps i think. not great and these are figures from top end pc's.
i think i have wondered too far but the bottom line is no, i dont think they will, BUT if any of theh consoles you listed were to be emulated it would be
N64 and possibly and i say this with enormous amount of doubt Dreamcast. the PSP uses a nerve system rather than polygons so thats gonna be a stupid task to try and emulate. since it uses a new system thats new to everyone its gonna be a long time before its emulated.
hope this helps