This is a problem per se.  It's fine to be bipartisan on an issue where both sides can agree, but what's basically going on here is business interests insisting that Democrats who've been elected to office nevertheless yield some power to the business class in the form of Republicans.

Politics are about people with differing interests advocating for those interests.  Only where those interests converge or can at least be reconciled are calls for bipartisanship legitimate.  Mostly this is just a right attempt to maintain the status quo in favor of business.

I would suggest Olympia Snowe. She is a republican who believes global warming is a serious threat. She consistently votes pro-enviroment, moreso than Hagel or Lugar.

I doubt Obama will pick her, though. Lugar is better than Hagel but that isn't say much,