K-Rod would be a nice get, but wasn't he insistent on wanting to close?
A reliever I'd think would be a good idea and probably wouldn't cost too much is Fernando Rodney. He's 39 and he's on the Padres who aren't going anywhere, so he probably is available and wouldn't cost too much. He has been one of the better RP in baseball this year and I think is a guy Sox should look at. I know he's inconsistent from year to year, but he's in the midst of one of his "good" seasons.
As for SP, I'm really not sure whose available. I know we mentioned James Shields and I'd be all for that, but I'm starting to think asking price is too high at the moment, as every time it sounds like he's going to be dealt, talks fall apart, which it appears is happening right now with Chicago. But based on whats available, I think a guy like Shields is much more likely then a top of the rotation starter as I just don't see one being available for a reasonable price.