The CAT Diesel Power mud flaps are available at your local Cat dealer. At least that is where I got mine. They had them on display right as you enter the store. Also the Cat licence plates and such. Mostly cheaper than on ebay too.
Jim
I found mine at the local Quinn/Cat dealer.
Some fool paid around $100 last summer for a set of pickup truck size! I'll sell you my xtra set then I can buy 5 more sets @$20