Vince,
I can really resonate with your sense of stream entry taking longer. I started doing a number ofshort retreats over the last year and with 2 retreats of 9-10 days I get into knowledge of A&P with both but don't cross. However with 2 retreats of 14-15 days, I managed to cross A&P, through the Dark Night and into equanimity. In both the 2 week retreats I seem to stall out in equanimity.
I seem to get stuck in the pleasant phases (knowledge of arising and passing away and knowledge of equanimity), and power my way through the difficult phases (dark night). Somehow the mental and physical suffering along with a deep insight that there is no "silver bullet" and clear knowledge that no goal, no thought, no thing, will satisfy drives me into intensive continuous practice and helps to fuel rapid progress. Then when the clouds clear and all gets easy and smooth, maintaining continuous disciplined practiced is a bit harder. As I try to ratchet up the effort to get things moving, the same kind of effort that got me through the dark night is too gross and I seem to start backsliding until I dial down the intensity
Disclaimer: all of this is my working hypothesis

One of the teachers at IMS that I consulted on this mentioned that for some "greed" types (I'm definitely a greed type) that's not uncommon. And that what I need is a longer retreat (at least 3-4 weeks or more) to allow time for me to get the hang of skillful effort in equanimity and to allow it to mature.
I just received confirmation on the March 2009 Month long retreat at Spirit Rock with Jack Kornfield. Hopefully this one will do the trick

-Lee