there used to be quite a few sites that sold them online...and now most of them aren't doing it anymore...I was looking to buy one myself...with a clear piece in the middle...but it seems the only way to get a custom one anymore is to make it yourself...
One of my buddies did this in his 99 cobra awhile back. Kinda defeats the purpose of doing a rear seat delete in the first place but it was nicely done.