Here it is: A 500, with 350 front fender, with 500 fender stays. The only tweaking I had to do was straightening the ends of the stays. The 500's curl on the ends. So I just stuck the ends in a vice and bent them slightly so they were pointing straight up.
Also, you'll notice there's no middle fender stay. The 500 was too short and the 350 stay was too long - not by much, but enough that I couldn't drill a hole. I've got enough stability with the front and rear stays that I don't necessarily need the middle ones, but I may make one out of flat aluminum bar and paint it black.
Also, check out Ace's air cleaner!