that pantry is perfect
get yourself 2 bottles of flat white spray paint and spray the shit out of the inside to make it reflective......
for ventilation you can use a couple of PC fans to circulate the air... they're the quietest, and you don't want a fan rambling if you're trying to sleep.... trust me...
www.newegg.com has very cheap ones.... i wanted to make it easy on myself and bought a pc cooling pad (they have a 3 fan one for 13 bux or so), that way the fans are already hooked up to a USB charger, i just bought a USB charging thing for an ipod at walmart (6 bux), carefully unscrewed the fans from the pad, keeping the USB cables together (BE CAREFUL, IF YOU DON"T KNOW ABOUT WIRING IF ONE OF THESE COMES OUT IT CAN BE A PAIN TO PUT THE USB-DC CONVERTER TOGETHER AGAIN) placed them on my box, and connected the fans to the USB charger.... and PRESTO!!! ventilation, quiet ventilation.... i used a 9" fan i bought at walmart on a cardboard box and it was a bit noisy..... this is SUUUUPER quiet.....
just so you know what i'm talking about:
here's the cooling pad I used:
KINAMAX President Notebook Cooler Pad w/3 Built-in 60mm Fans for Laptops Model FAN-NTP3 - Retail
http://www.newegg.com/Product/Product.aspx?Item=N82E16834987002&cm_re=cooling_pad-_-34-987-002-_-Product
here's the USB charging thing (mine was cheaper, go to the store and you'll find the one I mean):
Music Power Encore Dual USB Port Charger and Extended Rechargeable Battery for iPod and MP3 Players
http://www.walmart.com/Music-Power-Encore-Rechargeable-Battery/ip/5750793