No club in North Scottsdale has a National membership at this point, including Silverleaf.
Quintero and Blackstone have trial memberships, but are a 40 to 50 minute drive from the Grayhawk area (each way!) - I'm not sure that I'd put much of a deposit, refundable or not, with either at this point.
The TPC Scottsdale has an annual deal.
The discount cards offered by Troon Golf, Grayhawk, and the Southwest PGA will probably fit your situation best as long as you don't mind resort golf.