I have seen in NopCommerce project that there is a solution and there are multiple MVC projects within the solution.
I have some questions about it such as :
H
Yes it is. See: asp.net mvc put controllers into a separate project
I've done this myself and was able to use the controllers in a plug-in type architecture.
As for the models, they are just normal classes. They can be used in any project for any reason. There is nothing special about them.