Gray Sail Brewery out of Westerly, RI is a relatively new brewer who has struck quite a hit with their Double IPA, Captain's Daughter. Pretty hoppy, but still drinkable. Only available in MA/RI, as far as I know, but I enjoyed it!
Sean Lawson of Vermont's Lawson's Finest Liquids most famous beer is Double Sunshine, his double IPA produced in extremely limited batches. When Mr. Lawson decided that he needed to scale the business a bit, he set up an agreement with Two Roads Brewing on Connecticut to brew his modified Double Sunshine recipe as Sip of Sunshine. Originally packaged and sold only in kegs and 22oz bombers, the transition to 4 packs makes a ton of sense, especially in light of local competition in Vermont and the superior QPR of 16 oz cans. This is brewed monthly in CT and then distributed in both CT and VT. Great beer, comparable to Heady Topper in my opinion.
Trillium Brewery, in my view, is Boston's response to the Vermont beer scene's relentless quality. While Boston and the vicinity has a number of good breweries, none are truly great, especially when it comes to producing the renowned IPAs that are coming out of Vermont. I have had a number of great beers from Trillium, including Melcher St IPA, Congress St IPA, and Fort Point Pale, which drinks more like an IPA. Unfortunately, A Street, does not live up to the others or its $10 price tag. Still a good beer, but nothing special.