The very top of Lollapalooza should not really be green, but they need a green trail there for access to the Jordan Grand. Beginners really struggle there, and for that reason I'd keep it off this list. That said, it does make a good, easy lap for non-beginners.
Lollapalooza came to mind for me as well, but that's the first thing I thought of is beginners probably don't take kindly to the top of it. Tuckered Out at Okemo is a similar trail but not nearly as steep at the top (but is a blue, because Okemo).
Polecat was the first trail that came to mind for me when I saw this. First time since I was actually a beginner where I skied a green trail and said to myself "I could ski that all day" and at the same time it's a good trail for a higher level beginner. The Meadows at Stratton are great. Long John at Mt. Snow is a terrific beginner trail at the top and doesn't really cross many trails but once you get below Carinthia it turns into a total zoo. IMO some of the best beginner trails in the east are off the former Bucksaw chair at Sugarloaf, but now that the chair is gone there's no way for a beginner to get to them without dealing with steeper and often crowded connector trails off the Super Quad. A lot of the beginner trails at Bretton Woods are top notch and have excellent lift access as well.
The problem with most beginner trails that originate high up on a mountain is that they almost always criss cross down the mountain. It sucks for both the beginner who has to cross steep trails with people flying by, and for the people skiing those crossing intermediate/advanced trails who get a nice run interrupted by skidders with no sense of control. Obviously Great Eastern/Great Northern are the poster child for this, but almost every mountain has trails like this. I can't believe people are saying Mountain Road at Okemo...the top is flat as a pancake and about 20 feet wide, then when it heads back towards the base it crosses about 10 trails and becomes very crowded.
I never give Wachusett credit for anything, but the Monadnock Chair is one of the best areas for beginners in the area. Easy to ride high speed quad, two wide trails that have a nice consistent pitch, and no way to access them from the rest of the mountain or crossing trails. Not to mention a nice view.