Does anybody know how to make a custom BCL work with the stock CLR? How to discover existing the most essential ties between CLR and BCL and reuse them?
Here is what I have so far: http://lightnet.codeplex.com
Given the comments, it sounds like you want to use the stock CLR with a custom BCL.
I highly doubt that that will work. The CLR and BCL are likely to have quite a few ties with each other - they will make certain implementation expectations, and rely on them, not unreasonably. For example, the CLR may rely on certain internal types which you wouldn't know about.
I would be reasonably surprised if you managed to get the stock CLR to work with your own BCL implementation, although it would probably be significantly simpler to implement a custom BCL to work with the Mono runtime - at least there you can debug what's going on if you run into problems.