Samba has already documented the protocol and if it wasn't for licensing issues it would be very easy to port it into Wine.
Well, how easy is very easy? What I meant is that it's unlikely to be something you could do quickly unless you were familiar with the code in question.
It'd be a tragedy to reimplement all that of that code because of GPL vs LGPL concerns. I guess they can't just add an exception clause without consulting every single one of their contributors.
Given the ports problem, maybe the solution is just to have smbd expose an interface that lets you manage named pipe connections through it. Not thought about this problem much though.
I think you can just use UNC paths. The same applies for mailslots too IIRC.
I suppose that makes sense, yes.