Perhaps I am demonstrating my ignorance of some oft-used feautre of C# or the .NET framework, but I would like to know if there is a natively-supported way to create a type alia
If you look at the .NET Framework System.Uri is the closest example that is similar to an email address. In .NET the pattern is to wrap something in a class and add constraints that way.
Adding strong typing that adds additional constraints to simple types is an interesting language feature that I believe some functional language has. I can't recall the name of the language which would let you add dimensional units such as feet to your values and do a dimensional analysis on your equations to ensure that the units matched.