I'm 99% certain Boldin will not be traded; he hasn't signed an extension yet, but he will this off season--it's been called a top priority by Cards' brass. The sticking point may be that he could want more than Fitzgerald (and deservedly so, IMO).
The other names you guys brought up (Freddie Jones and LJ Shelton) very well could be invoilved in a trade. I'd say good riddence to bad rubbish in the case of Jones--he really stunk it up this year. He couldn't block my dead grandmother, he doesn't get any YAC, and even his pass-catching skilss seem to be diminishing.
Shelton, on the other hand, is a very good lineman. He battles some injuries this year, and fought himself (seeminly) out of Denny's dog house. i hope he sticks around, but that o-line will be blown up this offseason, and Shelton is a likely casualty, I think. It's be nice to get value for him in the form of Henry.
Personally, if I were the Cardinals, I'd probably start the bidding at a 4th rounder and Jones for Henry and go from there. I'd not want to give up more than a third this year, though.