I've seen many thread about M2Mod saying that we just have to ask to get the M2Mod source.
But I had no answer to my calls, so I've tried to decompile the C# project.
Here are the decompiled sources. I don't know if it can be of any help. I hope so.
I've decompiled the .exe with .Net Reflector + FileDisassembler.
Here is the repo:
https://bitbucket.org/Fr33m4n/m2mod/srcEDIT: updated with the real sources kindly given by Redaxle.