This project has been around for sometime but it is worth bringing back. @ Valkyrie-MT has implemented a TCP/IP stack using C# only. He calls it MIP. While NETMF has a built-in native TCP/IP with excellent performance, there are cases there multiple interfaces or custom interfaces are needed. Customizing/compiling/debugging the NETMF sources requires special knowledge and tools. Using this MIP stack, developers can easily step through the stack right from visual studio. The stack already include drivers for ENC28J60 but it can be modified to use others. Not to forget that the built in stack and the MIP stack can run simultaneously.
@ Valkyrie-MT original post is found at http://www.tinyclr.com/forum/topic?id=7703