Realistically I don't think the Pens will sign any big name wingers as they won't be able to match or better what other teams will offer for players like Kariya, Smyth, Blake etc.
Trading will most likely be the route to improve the team in its weakness on wing, IMO.
There have been rumors of Kovy ($4.5m), but with Boston now trading for Manny Fernandez, speculation is that they will be looking to shed some salary and Glen Murray($4.2m) is the name that is often mentioned. He's a right handed shot, plays gritty, and would look good on the first line with Crosby (i know, who wouldn't). Murray can still score, even without Big Joe being there. I think he would be a good fit on this team and solve the wing issue, all without having to break the bank.
As for the return, really not sure what the Bruins would be looking for as it has been rumored for over a year that they want to trade Murray, perhaps a combo of our "spare" parts would be enough, such as a combo of Christensen, Malone, Orpik, (the usual suspects) when it comes to trade talks.
Just my $0.02