I think with Calgary's "depth" on the blue line its far more likely you'll see Robyn Regehr traded before Iginla. RR is around a $4.5m cap hit I think, so moving him would solve some problems on that front. He's also younger, and a pretty defensively responsible defenseman, and as such should fetch a much higher return for Calgary than Iggy who's both more expensive and older would. Calgary doesn't have any stellar defensive prospects in the system, but in terms of blue chippers they are a lot better off than they are up front with only really Mikael Backlund to speak of.
In any event, Toronto is a very unlikely destination for either guy.
Most likely you'll see them bury salary or enact a buy out in hopes of retaining Curtis Glencross this summer. Otherwise i don't expect them to do anything too drastic as I do believe Hagman, Kotalik, and Sarich all come off the books in a year and that's about $9+ million worth of room.
Trading Iginla would very much make guys like Jokinen and Stajan that much more useless to say nothing of probably turning the fans against the team that would otherwise have nothing else really to offer them (unless they are able acquire a pick in the Coutierier, Nugent-Hopkins range)
Oh, in regards to a few posts back and in speaking of Regehr... It was Regehr and Phaneuf that had the problems in the dressing room as opposed to Iggy and Dion. Phaneuf has always spoken highly of Iginla and even said that when he became captain of the Leafs the first call he got was from Iginla.