I'm a Rhino modeller myself, difficult to beat it imo (at least for the price).
So which bits did you model in Alias? How do you find Alias as compared with rhino?
Ref the sea reflections - I used to render with lightwave and had to do composites of the sea to achieve good renders. I'd render out the boat in one pass, the foreground sea (displacement mapped) in another and then the distant sea (a bump mapped plane), then fudge them together in photoshop after. What a pain!
Your exterior renders shouldn't be taking that long to render, unless the Alias renderer isn't too efficient. I think you should be able to render one of those views at 2k res in a couple of hours (with full GI). Take a look into 3dsMax along with one of the 'plugin' renderers, should speed things up a little.
For the moment though, I think you could get away with not having those close horizons by cropping the image to a different aspect ratio.