[gwerbin]

OCaml is a better candidate than most. It already has a macro system (PPX), and the core language has a lot in common with Scheme.

[rixed]

The PPX macro system is far from perfect, that's the whole point of this idea: with the native REPL + an s-expression syntax, you have lisp-like macros for free.

[classified]

S-expressions are more than mere syntax. Lists in OCaml can only have a single element type, so you would need something different for s-expressions.