This is only really of use to the FCP X editors, I've just put my first Motion theme for FCP X on the App Store:
Mac App Store - Electric Guitars Theme for Final Cut Pro or Motion
I've got a couple more due soon and some effects to follow. I'm not sure whether to keep the payloads shopping cart options on my website or not.
Perhaps I'll add future stuff there while waiting for App Store approval, I'll see how things go.