Having spent a lot of time at IMS over the past few years, I can totally relate to your frustration. While I've never run across a teacher claiming that stream-entry wasn't possible, I've seen plenty of disempowering models and statements made by some of the teachers at the IMS. That being said I've also been really impressed with a couple of the teachers, though it took sitting with them for months of time to finally get a sense of their actual views and opinions (separate from their public talks), and to find out that many of them are quite realized and are at least anagamis (using Daniel's criterion). Also, many of the teachers there make claims to stream-entry, though you have to deduce it form what they're saying.
Some of the teachers at Spirit Rock, particularly Jack Kornfield, John Travis, Howie Cohn, & Trudy Goodman are very competent and realized teachers. They also seem to have better models about enlightenment.