Our work product is a bit unique in regard to how our pages are coded. Due to the high amount of inheritance in our pages we implemented all the pages in class files which inherit Web.UI.Page and just had .aspx page stubs which pointed the code behind to this class. This worked well until we hit the annoying issue of having to synchronize the aspx files between resources, and making sure they pointed to the right level down the inheritance chain. A messy solution was presented which was hard to maintain, so I did a bit of research and by using a HttpHandler I found we could solve our problem by keeping all pages inside the dll itself.
I have included the code for the concept below and a small sample of how its used.