Maybe just a couple of big fans (120 or 140mm+) and a cheap thermal controller would do ya. Just cut out holes in the back of your stand and mount the fans there and plug them into a thermal controller like this one here:
http://www.coolerguys.com/840556086611.html
That one is pretty cheap ($14.00)... it won't turn on with your receiver but as long as it turns on when it warms up inside the case it should be fine I suppose.