Let me give some additional context: I think this is very nice work. However, I would like to be able to replace XML literals in Scala 3 with a xml"..." string interpolator. So far, that proposal is on hold since we want to have a good official interpolation library in place first. We would hope to be able to ship such a library with the standard Scala 3 distribution (this would be an exception to the comment in SIP: Curried varargs - #38 by sjrd). I see a lot of potential for a variant of name-based XML literals to become that library. So, I would be happy to see a worked out proposal along these lines.
One other remark: Scala-3 macros are typed so we cannot simply issue an identifier and hope that it can resolve to something. However, it seems the desired effect could be achieved in a safer way with implicit function types. I.e. the interpolator would generate instead of an XML tree an implicit function type that takes implementations of the generators and yields an XML tree.