Except for GTAIV.
Well, anyway, a laptop that can handle PS2 emulation is really... asking a lot. You won't just be spending a fortune on that, you're literally asking for the absolute strongest laptop on the market. Battery life would be more than horrid, too, of course.
A laptop that can play most newer PC games wouldn't be asking a lot, though.
In fact, I'd suggest getting a compact LCD and building an HTPC with a decent Core 2 Duo clocked to over 3GHz. Should set you back around $900 for all of the components (assuming they're the very good ones), and would do about the same thing as the laptop you're asking for. Plus you can put them both into your backpack and haul them around all over the place.
If anything, they both have to be plugged in when you are doing PS2 emulation or playing PC games... so... might as well get an HTPC, which will obviously be able to do almost full-speed PS2 emulation in most titles.
And no, Phil, that's totally legit.

You should have a hint of what my desktop looks like now... as well as the specs.