Hello. 

I have not thoroughly read your posts, 
but it looks like the double vision problem. 

You may be interested in the following post to camllist:

http://caml.inria.fr/pub/ml-archives/caml-list/2007/06/0d23465b5b04f72fedecdd3bbf2c9d72.en.html

By the way, I believe one can hack the OCaml type checker 
to (mostly) avoid the problem by "strengthening" 
the external signature of the recursively defined module 
in the type environment. But this is not particularly beautiful 
since a type constructor may escape its scope, 
although the implementation is kept sound. 

I would be very happy if you could give me a practical example 
which suffers from the double vision problem. 

A happy new year!
Keiko