The final cut of the 9th episode of the Tesla Motors Club Podcast, featuring Chad Schwitters, the former president of Plug In America, is now available. You can watch it now on YouTube or listen to it on all major podcast networks.
Most any should be able to do it. I'd recommend going with a local one. In Chelmsford I used Village Electric, and they did a great job installing a 100a subpanel in my garage and a 14-50 NEMA outlet. I have used them for several other smaller jobs. They are not a small shop, not a big shop.