Punk already has about 3 or 4 (maybe more) Best of DVDs so I don't know that'd be absolutely neccesary but it could be cool for a complete set.
Getting ROH footage would be more difficult. They'd have a better shot at getting IWA-MS or smaller independents footage. Of course, they would probably only take footage against other current WWE talent such as Sydal, Gibson, Cabana, Kendrick and Kennedy. I would hope they have more OVW footage then anything else.
If they did get IWA-MS footage, they could just grab the triple threat Punk/Mysterio/Eddie match and maybe a Punk/Eddie singles match. The major crutch, besides there being no real precedent that I'm aware of of DVDs using indy footage except for The Hardys in OMEGA, would be that Ian Rotten isn't exactly the biggest McMahon fan. Then again, given the chance, I'm sure money would talk.
Wasn't the Benoit/Regal match on the Benoit DVD an indipendant show...or was that run by WWE (which I doubt, given the bad camera for it)?
You're thinking of the match they had at the Pillman memorial show. It wasn't really put on by WWE but had WWE talent there.