Implementation size is hard to compare accurately across languages (bytes? lines of code? exclude comments? excluding leading spaces?). Also, the mal implementations were created by many different people so individual style plays a large role in concision/verbosity.
However, that being said, the following implementations are "smallish" (in both lines of code and bytes): mal itself (self-hosted), Clojure, factor, Perl 6, Ruby. The following are "largish": Awk, PL-pgSQL, C, PL-SQL, Chuck, Swift 2, Ada.
OCaml is in the "smallest" third of the implementations.
However, that being said, the following implementations are "smallish" (in both lines of code and bytes): mal itself (self-hosted), Clojure, factor, Perl 6, Ruby. The following are "largish": Awk, PL-pgSQL, C, PL-SQL, Chuck, Swift 2, Ada.
OCaml is in the "smallest" third of the implementations.