As far as I know, no previous trades have been rereleased as MMPBs. Am I wrong about that?
Yes, you are. The Lives of Dax
was originally a trade paperback and then was re-issued with the post-finale Deep Space Nine
logo as a mass-media paperback. I think there was another case, but my head cold is preventing my brain from working.
Hm. Thanks, I had forgotten about that.
Either way, it's not particularly common.