Kenne Bell makes one and so does Postons but Marks I think is the best one. I have Postons because I didn't know about Marks when I bought mine. There is a good article somewhere on gnttype.org if your going to make one.
I have had to do a little home modification to it so it would be up to my standards. I put a rubber seal like the one Mark uses in his setup so that there is no air getting in between the MAF and the canister that the K&N sits in. Postons did't provide anything like that so the filter was still sucking in alot of hot air. Then I relocated the air/fuel canister to were the old air box was and cut a whole were the air/fuel canister sat this made it so the tubing would be straight on from the scoop to the air filter canister instead of taking a bunch of turns and constricting.
If your going to buy one buy Marks It doesn't requier any relocating of any kind not to mention the K&N filter is outside of the engine compartment were it stays cold. I've been thing of doing something similar like his setup for awhile I just can't find the right equipment to make it look good.