I think the trouble with building modern subs for Silent Hunter is that you really need a whole game to use it in; for me, tearing around the ocean at 30+ kts blowing up everything in sight would only be fun for a few minutes.
However, I do think it would be cool if someone (or a group of someones) put together one or two modern boats. Hell, how about some early Cold War boats like the Nautilus or Skate? There's plenty of photos of those, and the tech wasn't drastically different from WWII yet, either.
