Part of the mac address identifies the manufacturer of the device. The rest is defined by that manufacturer. With that, you're narrowing down the possibilities a bit -- i.e. you know that it's a wireless device made by Intel.
You're not narrowing it down too much though. Most Windows laptops I've used in the past five years all use Intel made internal wireless cards.
And... it's not too difficult to spoof a MAC address.
If you know the MAC address of the intruder, why not just block it? That won't help you identify the perp (unless somebody complains that he/she can't connect), but it will secure you a bit more--
Age is a very high price to pay for my maturity. If I can't stay young, I can at least stay immature!