I don't know who might be out there in FA either but if we were able to stretch higher in the draft to get a true LT I'd be in favor of that. There are always pass rusher out there and you can find some later in the draft as well but you seldom find a capable LT last longer than the mid part of the first.
I mean, the worst situation that the Bears can find themselves in is another year with Webb at LT. While that may sound depressing, he will have had another year of seasoning and an actual offseason to hone his skills to the point that he might be a bit more effective. That being said, if push came to shove, Tice could always instruct his new OL coach to move Carimi to left tackle and move Webb to RT, though I have to admit that along with a couple of other people on this site, that is not a likely scenario.
As far as the first round is concerned, we could trade away our first round pick in the 2013 1st Round pick along with the 2012 1st Round pick and maybe one of the thirds in order to get one of those two top ten draft picks for a LT (Reiff and Martin). This would more likely happen with Les Snead should he get the job than Marc Ross, if the Giants past drafts shed any light on this matter. That's my wild hair-brained scheme of the day/night/early morning.