Too bad you didn't oversize and route a marquee goove in the bottom panel of the marquee box. That way you could have just layed the lexan in there and made your own top bracket.
Now, I couldn't see it in there, but I think having a top bracket (just a different idea, nannuu, bear with me, I'm not kicking your idea down) isn't necessary, looking at your design.
KrawDaddy, since you have a router, what about this for your marquee:
Get a
1/
4" channel (or box or whatever they name it by you) bit, and use a hardboard template and bearing guide to make a groove on both the top and bottom panels of your marquee box. Using 2 pieces of
1/
8" plexi to sandwich your marquee between, it should easily bend to fit the curve of your marquee, keeping the original shape, rather than a curved front with a "boxy" and set back marquee.
I really can't craft a picture to show you, but I have a feeling you have already been thinking of this when you went with this marquee design.