I came across this today and thought there might be interest in this on the matplotlib list.
"reinteract" is an edit-in-place shell, that includes rudimentary matplotlib support.
It's still in its early stages, but the approach seems very promising. Be sure to watch the screencast past the half way mark where the author demonstrates the matplotlib integration.
Science Software Branch
Operations and Engineering Division
Space Telescope Science Institute
Operated by AURA for NASA