Hi Bradley
Not 100% sure of what you want, but one idea would be to use balsa for the frame/details. It should be easy to design some of the art deco type straight lines. Another advantage is that lines/designs can be drawn/pressed into the balsa, and these will show up nicely during painting by the usual painting tricks (drybrushing & washes). Cardboard could even be used for finer details.
Just google art deco and paris and see what you come up with, and then adapt this for your window!
For the glass you could use "overhead" plastic sheets and even print some stained glass on to it!