I agree with Jarrod. Now is the time to negotiate and if they think highly enough of you to make you the offer, they will work with you I'd imagine. Even if they don't, the worst they can say is no and the offer is still on the table. It's like going for a hot chick, you'll never know if you could've landed her if you never tried.
My wife and I are actually right in the middle of relocating to California. She's staying with her company, just relocating, and it's been an interesting process negotiating with them. It's an extremely complicated move package being that we're going from a cheap place like TX to CA. From the time that she found out she got the promotion to the time they actually gave us the official move package, we came up with minimum numbers in different areas of it that we needed to get. The offer actually came in higher in every category so we had decided we were going. We countered in a few different areas of the package and asked for some of the "that shouldn't be a problem's" to be put in writing. Ultimately, they accepted every part of our counter but refused a very slight adjustment in the base salary. They kind of shot themselves in the foot with it too as the one thing they wouldn't budge on, really was the least costly to them when they gave in to everything else.
Anyways, sometimes with companies, there are so many people involved that they can't see the forest for the trees. You only get this one shot to negotiate so take full advantage. I'd counter with salary, stock, free hotdogs, parking, a new car, gas allowance, whatever. You might be surprised what you get.