I would trade the eevee I have, but I *think* it has the exact nature my brother wants.
I put a pokemon in the GTS for Arcanine so that'll for for you (just need to breed it for growlithe)
Edit: I got the arcanine here. So, what'll happen is that you can get a free level 60 mild poffin if you go inside the hearthome city contest place and talk to the first person there sometime - I'll trade a female growlithe sometime if you feed a pokemon of mine that particular poffin (doesn't have to be immediately). Deal?