Yes, there are SS filters available. Scott's for sure makes them and you can get them from most large KTM dealers. Try Mike Krueger at Cycle Zone KTM. Tool free at 866-843-7433.
You should be aware that they will void your warranty, though, according to the KTM USA service dept. The last word on that, and it's been a while back now, is that KTM is testing the SS filters to see if they will approve them or not.
Mike can also sell you paper filters cheap. I think I pay just under $10 a pair for them from him. Most guys are going 2-3 oil changes before changing filters so that's pretty economical.