I have an open filter, as well, but I have yet to find out who makes it. Way better than any of the covers, in my opinion. For you guys with the CD insert, a couple coats of clear over the disc will help to prevent scratches. Those CD coatings are fragile.
Lots of cool ideas here. I have a basic round cover. But sometimes I just run it without and put the breather cover bolt back in the hole. ANYTHING looks better than the stock cover. The stock cover looks like something you would cover up room service food with at a hotel.