We are using NSB as a send only endpoint in a REST style service hosted in ASP.NET. We are using unobtrusive mode and thought it would be easiest to identify our messages via using the assembly name itself. We unit tested fine, and our server side worked, but the client side just failed.
We forgot about the whole dynamic compilation thing in ASP.NET. So we had some choices we could either go with fixed names or we could change our convention. We went with the latter. So be aware when you're dealing with ASP.NET.