I was just researching the same thing, and couldn't find (on the internet) anyone selling klx number plates/fenders without lights. I know I've seen 'em, so please let me know if you've found anything.
Two change to a number plate remove the stock lite and install a KX front number plate. As for the rear Maier makes a MX style rear fender for the KLX. You can get one directly from them or Stroker Speed Equipment sells them also. Maybe some other places to but that's all I can think of right now. Hope this helps.