My San Diego experience:
I got completely different answers from dealers here in San Diego on 2017s. Most would not take a deposit, Toyota Carlsbad finally did, $500, fully refundable. I got on their list at 10th in line, requesting Cement Gray. They feel that around half of the folks on the list, despite deposits, will bail on the purchase. They also guarantee selling at MSRP. Kearney Mesa Toyota said they be selling (attempting...) at $7500 over MSRP. Toyota of El Cajon would not take deposits and said first come first serve. Lastly, knowing how large Longo Toyota in LA is, I called there, I think they said their list was around 28 folks deep and advised that they felt it was unlikely they could get that many vehicles.
All over the map here....
With the advent of the new TRD models, I suspect that production volume will be much higher than 2016 for the TRD Pro, but that's obviously speculative.
Good luck to all!