The Gateway FX series are well known for being the best bang/buck gaming notebooks on the market. Their construction is noted as rather sub-par, but you get what you pay for.
Otherwise, you could go with a Sager NP8660, but I'm not sure ATM what the price rolls on that to be.
The only difference between upgrading processors on a notebook and that on a desktop is there's a bit more work involved in dismantling a laptop. Hard drives are easy as pie.
Upgrading the CPU will not affect DX10 performance, though. That's GPU territory.