A question about windows

I am not even close to putting in windows yet but they are on my mind. I would like to have a mostly glass roof over the bed but my concern is condensation and leaks. How would I go about building a custom window that will not leak or drip condensation on me while I am sleeping. I realize that I will need to caulk every seam but as for the condensation I'm not sure. Should I try to make a dual pane window? What material should I make the window out of? My roof will be curved so glass is out of the question, but I was thinking Lexan or a thicker Plexi-Glass. What do you guys think?
Thanks for the help.
Josh
Thanks for the help.
Josh