It's all in the approach. Most people considering a Chainmail/D&D experience approach it from the perspective of adding Chainmail combat to D&D. What about taking the approach of adding certain D&D elements to Chainmail. There is a philosophy amongst the OSR that it is easier to house rule things in, rather than yank them out.
That being the case, the first thing that needs to be done is to clarify and clean up the Chainmail elements we will be using, namely combat, magic, how magic items function, and monster stats/descriptions. Secondly, the elements from D&D that will be needed have to be identified and retooled to conform to Chainmail. That's a bit of a two-sided sword. Most of D&D is written with the assumption that the reader owns and is familiar with Chainmail. So, some of the work is done. Unfortunately, the veil between Chainmail and D&D is rather nebulous and the voice of the rules slips back and forth without warning.
I've contemplated this on here before, but it never really gained critical mass because I just couldn't get my mind around how to integrate Chainmail's wargame combat into D&D's roleplay arena. Then I found these guidelines at Howling Tower (thanks, Steve). This was a major hurdle for me, and now that it is out of the way, maybe I can move forward. As always, I'll keep you posted.