I'd recommend an open minded look at some of the more high-end composite styles. Not the gray or brown Trex you see in HD or Lowe's.

There are some very attractive materials there. You might need to do some out-of-sight reinforcement since the joist spacing is less for composite than traditional planks.

If you prepare the material properly you can also use stains on it, so color matching and sun fade or bleaching are controllable.