^^^Looks like a custom job. As far as I know, this is the closest thing commercially available, even though it's not what you are looking for:
http://greggscustoms.com/?wpsc-produ...der-eliminator
I know its not what you want to hear, but unless you can find someone willing to part with a one-off or maybe someone who made a few extras, it's going to be a DIY project.
Some DIY projects turn out really nice, a guy on this forum did a great job fiberglassing that portion smooth on an OEM tail.