In SoCal - just recently had Tesla complete a proposal for Solar PV system with 2 Powerwalls and a site survey.
I backed out because Tesla CAN NOT reserved SGIP for me because they have fully used their quota. Overall my sales agent and plan designer were awesome but NO SGIP means a lot for me, to the tune of about $6K - $8K loss.
I can give you both contact info in you want to go ask them - send me a message. I can also share you price breakdown per Tesla for PW vs my local certified installer - this was as of Feb 14, 2019.
FWIW, there are local certified installers that still have SGIP reservation quota. The one I just signed a contract with promised in (email/telcon) that they have the Powerwalls in stock, and in CONTRACT to complete install within 30-90 days of contract signing. PLUS they can reserve SGIP.