I remember pushing my Core 2 Duo from 2.33 GHz to 3.15GHz. I think it needed extra voltage at that point, and it made the cooler too loud. But at 3GHz it was stable on stock voltage.AMD did announce laptop APUs at CES but I dont remember when they are coming out. I would guess maybe 3-4 months away.
The last overclock I had that high was on a 8800m gts, I remember getting 31% on the core and 35% overclock on the memory. Back in 2008.