Has anybody replaced the boxy F2F3 fender with something a bit sleeker. Are there any other model of front fender that will bolt right up?

 

Nothing will bolt right up, but I have seen a few members put R6 fenders on their bikes. When I asked how they mounted, they told me zip ties (matching whatever color the bike was) From the photos, the fender looked a LOT nicer and you couldn't tell it didn't belong.