Need help locating a second Lightolier glass diffuser/shade  

Over the last several years, I have been casually looking for a 2nd glass shade to a Lightolier wall sconce to replace the one I broke (Argghh!). The fixture has two matching glass diffusers side by side. I find no identifying model numbers on the light fixture, although they may be on the back where I can't get to them. The lamp dimensions are 16"L x 4.5"H x 4.5"D. It houses two light bulbs. Can anyone give me an idea where I might find a matching diffuser/shade?? Thank you!
http://plus.google.com/photos/106928913572006239560/albums/5844182332481641473?authkey=CM2Kg8SCx4WjoQE