Welcome!
Finding GMS on a Z06 *is* a tough. You will not get GMS on the low APR (at least this round).
See my thread in the dealer experience section on GMS:
Where I got my GMS discount
Unfortunately, I have heard my dealer isn't giving straight GMS anymore on Z's. I've heard there is a mark-up. I'd give'em a call and see what they say.
If none of this pans out, get on the phone and start dialing! I suggest cold weather dealers (where sales should be slower).
Allocations are being cut back for the holidays. One of our forum vendors (Hi Rick!) suggests that there will be a bit of pent-up demand when production resumes in January. So it may be a while. Though in this economy, I think a lot will depend on incentives. That may work in your favor.
Also, make sure you *KNOW* the dealer's allocation status before you play the 'waiting game'. I suggest requesting a copy of their 'YY37 inbound sheet' if things start to get serious. That will show exactly what allocations they are really getting.
Let us know how it goes!