From multiple reports Warren has been huddling with her advisers and trying to figure out how to move forward. A number of reports seem to suggest she is seeking the VP in exchange for bowing out...
Now, I find this very interesting, because while Warren is arguably the most aligned politically with Sanders, the evidence seems to suggest many of her supporters will not, under any circumstance, vote for Sanders.
I'm not sure if such a move will help Sanders or hurt him. I tend to think the latter.
Personally- I think both would serve better in the Senate, especially since they have helped push the discussion to the left. Hell...maybe Bernie would finally accomplish something in the Senate more meaningful then a post office for VT....