I could try to implement it but I would need a Windows machine to try it and I do not use Windows.
Anyway, if you can take a look and figure how to create a SASL driver for that protocol looking at the others, I can help you to integrate it.
Looking at the RFC it seems negotiate works with either Kerberos or NTLM support. The SASL package already supports NTLM, so I suppose it is possibly not a big deal but I would need time to investigate. If you can do it yourself looking at the code and the RFC, it would be nice to contribute back what you implemented.
ietf.org/rfc/rfc4559.txt
Other than that, feel free to ask questions so I can help you to do it.