Well Avian and Lee have been pretty strong champions of his legacy when it comes to Chorus Line, anyway...
PJ, it's nice to see some of the Ed Sullivan clips show back up, online (I still can't believe what a treasure trove they're sitting on--I have 8 VHSes someone gave me of various Sullivan musical clips, and I know I'm still missing a few--and currently have no VCR, so...). I especially love the Henry Sweet Henry dance, which is mentioned and shown in Part 4 of this lecture with his old dancers
http://www.youtube.com/watch?v=i6YqWziXM2E&feature=related Where is the performance you linked to from?
And I'm with you about Bolero D'Amour--I hope the legacy of this revival isn't that people think the dance is extraneous, as I've heard some justify it being cut. In just a few minutes, without one word, it completely sums up the main theme of Follies, and I think it's pretty sad that it was cut.
Besides the numbers mentioned, I'd add the Grapes of Roth from Promises Promises (maybe going into Turkey Lurkey), as that's the other piece of choreography many mention from the show as standing out (Mandelbaum says otherwise Bennett's main contribution was how fluid he made the scene transitions which usually used dancers).
It's long, and A Chorus Line is by far one of his better known pieces thanks to the length of the run and the revival, but I'd definitely add the Montage (if it's to show off Bennett, I suppose they could cut out Nothing from it), which is just one of the most thrillingly staged dances I can think of.
I know he came to Seesaw late and so it seems he never really had one huge stand out number in it, though his choreography got a lot of praise--the most famous dance (which my grandma always talked about seeing)--Tommy Tune's balloon dance for, I believe, It's Not Where You Start was I think mainly choreographed by Tune himself, and much of its appeal seemed to be about Tune's performance, and height, so it may be useless to restage... The opening My City maybe, it seems something should be used.
As TheatreKid said, it would be a daunting, expensive production, but would be worth it while people could still help recreate the numbers.