Bill,
Down here in the south ( Texas ) we want all the shade we can get. A typical C34 bimini here is about 10 feet long from front to back, which makes it extend from almost the back of the stern rail to about a foot past the front of the companionway. If we normally had dodgers here, the separate bimini would be a little shorter. It is made of 2 sets of bows that each include an additional fold-out shorter bow that fold out toward the middle of the cockpit area. They always are mounted on the top of the cockpit coaming and/or deck and definitely not to the stern rail: the bow geometry would be very poor and result in a very poorly supported bimini.
As for lexan windows in the dodger, I have been on a lot of offshore capable boats of all sizes along the Texas Gulf coast, and I have never seen lexan used for windows in any soft dodger. I have seen them used in hard dodgers, however. Lexan would be almost impossible to machine sew onto canvas/Sunbrella as it is very brittle. You might be able to hand stitch it if you drilled a series of "needle holes" along the edge for hand stitching, but this would also produce a whole set of other problems. Lexan in thicker panels is used for bullet-proof windows, so I doubt that it is a good candidate for any type of needle sewing.
John