I've never seen one in the wild (in fact I see very few 'bents on my ride) but I've seen at least a couple of websites where people had built fairings, boxes, etc for their 'bents. How they look all depends upon the quality of construction and to some degree the materials used. Some of the pics I've seen show well made boxes that are nicely finished off. I'm sure by now you've already Googled some of these builders.

I think you should go with wood built into the graceful curves you see in Shaker boxes. You could build up layers of veneer or use some 1/8" plywood that could be bent to shape. Maybe you could inlay your initials or family crest into the lid. Seal the whole thing with 2-3 coats of clear epoxy and then 3-4 or more coats or exterior varnish and you will have a real work of art attached to your 'bent.

While nobody will know your name, everyone will remember your bike. Heck you may even be invited to park such an artistic bike inside at fine restaurants, galleries and other establishments. Good luck with your project and post a few pics so we can live vicariously.