Well... you could lower the ceiling in the closet - seal it off and vent it up out of the grow area...

Basically put up a false ceiling a couple of feet below the real one, making the closet a little shorter, but 2 individual sections - Then hang your lights and such from it, and vent out above that to exhaust the heat/smell.. I've had to do similar when dealing with vaulted ceilings

You can get a really powerful, quiet fan, and connect it between the carbon filter and the light, so it pulls through the filter - I'd recommend a cool tube style - then the light is being cooled with the de-stinkified air and you can route it all out through one exhaust hole and you have warm non stinky air