There isn't such thing, and I don't know whether it's planned, but there were some very capable and infomred sounding people on the pyblio mailing list discussing the general future of open source bibliography handling. They were discussing grand style though, and I concluded to not expect any practically usable bits soon. If I had plenty of spare time I'd learn python and see if something like this could be implemented.
Hi again,
Meanwhiele I found out that pybliographer can search on PubMed, but only on PubMed. If you're interested, try menu File -> Medline Querry...
Cheers, Conrad.
