My familiarity with .NET in this regard is fairly limited, but I was wondering what would be required to expose modules written in Common Lisp on top of .NET to other .NET modules.

I'm afraid the answer might be some CLR Lisp implementation, of which there are few (if any) that are very mature that I know of.

Basically, I have a fairly involved (LispWorks) Common Lisp module that was originally the entry point for a number of applications, which itself made calls to .NET components. The requirement has come up that I expose some of it's features to a .NET application and I'd like to avoid reimplementing all of it in C#.

I'm not sure this is even an RDNZL question, but given that is my starting point I cannot help but wonder whether people have encountered the same issue given the nature of the problem RDNZL is solving.