My email is on my website, if you have any other questions feel free to shoot me an email.
If you have it, you know you can just implement syntax-rules in syntax-case? I do believe that is how chez, guile and racket does it.
If you're wondering how the hygiene works, each Identifier besides its name includes a set of "marks" (random unsigned integers). Identifiers are only equal if each name and their marks are equal. There's quite a bit more to this, but I feel you may be aware of how this works.
I do know. I haven't done that yet for no real practical reason besides some vestigial code that I have yet to remove. They are basically implemented the same already, under the hood they are both just transformers, I just haven't removed the AST code for syntax rules.
I found the syntax-rules implementation but didn't really see any part of syntax-case. Did you mean you support syntax-transformers in general (together with what looks like a very nice syntax-rules implementation), and not syntax-case in particular?