Unfortunately the only one I have heard about involves fabric...but I believe I heard it on the Nate Burkus show while he was still on air. He says treat it like a regular window. Put your rod, etc. ABOVE the arched window and dress it like it was one not two windows. Cannot totally quote because it was awhile back. I have the same windows scattered throughout the house. Not easy to deal with!

There are wood plantation shutters that fit arches but I don't think they will go with your current wood blinds. What about putting a solar screen on the exterior side of the arch, or adding solar film?

Hmm....I didnt think to use a film on the arch portion only. Good idea!

You could do a custom roman shade which would have the arch of your window. It could be a purely decorative valance and although it would look like it would lower the whole way, it would only have a couple of folds of fabric caught up at the bottom.

Call budget blinds they have all kinds of products that can be made in an arch shape. Shutter, woven woods ,wood, honeycomb. Check them out

Redi Shade for arched windows!

EASY AND INEXPENSIVE

http://www.redishade.com/store/rs_arch.html

These are wood and can be painted.

http://www.blinds.com/control/product/productID,8297