Got all pvp items that I need, so I am wondering about this.
You can buy various trade goods, crafting materials, etc. with Spirit of Harmony though. There's a vendor at the Shrine of the Seven Stars / Temple of Two Moons for that.
Perhaps on new PvP mounts... hmm no
New PvP tabards then?.. What, there arent any new ones for years now?
Can you change them for JP, they seem to be helpful for... nothing really...