I have a thread on this over at gm-Volt.com, but figured I'd cross-post here in case anyone doesn't read over there.
I bought a JDapter from Quick Charge Power (Tony Williams) this week. It allows any standard J1772 car to charge on Tesla HPWC and UMC EVSEs. It does not work with Superchargers.
I ordered using promo code JDAPTER239, which brought the price down to $239. I ordered Wednesday, he shipped same day, and I had it on the other side of the country on Friday. The unit is very well made. He even included a small padlock to lock the JDapter to the car, discouraging theft.
I tried it out yesterday on my Spark with a Tesla HPWC and it worked great.
Anyway, if you're likely to run into Tesladesination chargers, check it out.