Here is one of the windshild options Im leaning twards.
The other I am consindering is to make the roll bar look like a tracker windshild frame and bend some lexan around the front.
Ugh... Think about the rain, mud, and snow that would get on that design of roof and then would trickle down right down the center and then, if your moving, spray you in the face and, if your going slow, drip in your lap. My advice, don' t have a drip channel right down the center of your roof leading to the front of the vehicle. YMMV
-Eric