I just wanna add that there is also a dedicated group at Utah working on hygiene and macros for Racket, headed by Matthew Flatt (who's somewhat relevant within the scope of Racket).
(Not contradicting you; just wanna throw my school in where I can!)
I think you mean Flatt's "Binding as Sets of Scopes" [1]. Yeah, that's definitely something he's working on. There are a couple PhD candidates in his group who are also working on macros and hygiene, but I don't follow their research directly (we're just often in the same room so I hear about it).
Ah, I wish I could tell you! He's recently taken on some more teaching duties, so I dunno to what extent that is impacting his research abilities. (Hopefully not too much!)
(Not contradicting you; just wanna throw my school in where I can!)