Mark, I bought an artograph 1530 booth when I got back into building, as I too was wondering how I was going to paint thru the winter.
granted, it is a wee bit expensive, but, it is mostly metal, fits rig trailer sides in it, and is triple filtered. I absolutely love it, and would be lost without it. I paint all year 'round indoors, and if you keep the filters clean, it really knocks the smell down, so much so, I don't even vent it outside. again, a bit expensive, but in the long run a great investment in my opinion.