There is a white Denali 2.8 4x4 LB at Gunn GMC in San Antonio, TX. It just came in and is not on their website yet.
This dealer has fixed pricing and offered me a price about $4K off MSRP. USAA discount would be another $750 off in my case if I were to buy it under my personal name.
I'm only posting because I came across the exact spec I was going to buy but I'm going to wait for a 2018.
~ good luck.
Current: 2009 Canyon CC I5. 170K miles. Best vehicle I've ever owned.
Eagerly awaiting 2018 Canyon Denali Diesel 4x4 CCLB