Well, besides N64, I can't think of much that NEEDS overclocking.
PSX works nice with default 500MHz with a lot of games, but it hasn't been optimized and isn't playable yet (it has no frameskip at the moment and runs as fast as it can, so games run between 30 and 70 fps).
It runs in software mode currently, so yes, it might need a few months work, but it shouldn't need overclocking.
The Quake 3 I've shown in my videos were also running at 500MHz.
Basically, ALL videos I made were at 500MHz. Vice, UAE4ALL, latest Stella, etc.
All running fullspeed with 500MHz.
And I'm sure stuff can be optimized a lot
Heck, remembering back the GP32 days, nobody thought Genesis was possible, as NES was already a fight to emulate.
And at the end we had a very playable emulator.
Then on the GP2X, the first SNes9x ran with 3fps (snes9x 1.39 - the same recompile runs with 40 - 60 fps on the Pandora).
Nobody thought the GP2X could emulate the SNES well, but with PocketSNES, it was very playable with most games.
Now, we're at the beginning of the Pandoras' life.
Vice is fullspeed. Stella is. UAE4ALL is. GPFCE is.
N64, SNES and PSX need more work. SNES9x needs a nice GUI and some scaling work, PocketSNES is using a messy code that needs a bit more porting work.
So yes, don't expect ALL emulators from the very beginning - but I doubt it will take long until SNES will appear on the Pandora with a nice menu, VSync, etc.
Overclocking? What for? Except N64 perhaps.