I just built something similar to this...
You're gonna need some way to cut a few holes into your cabinet and a few fans, one for fresh air intake, one for exhaust, and maybe a few smaller ones to make sure there's good airflow in the cabinet (good airflow will help prevent certain foliar diseases as well as strengthening plant stalks). Of course, if you're "stealth" growing you'll need some sort of scrubber to remove cannabis odors from the exhaust, such as an inline activated carbon filter or some other odor eliminator like ONA. (My cabinet is still waiting on fans, unfortunately.)
That light setup you have is nice - I'm enjoying bringing up my own garden with flouros and cfl's but I still get jealous when I see other growers' HID rigs - but it's gonna put out an awful lot of heat in that small space, which is another reason why good airflow is going to be essential to your setup. You're making too much of an investment on these plants to just let them cook. I'm not growing anything significant at the moment, and won't be doing so until such time as I've installed a proper intake/exhaust system, as I'm not a real big fan of dead plants. Gardening like this definately teaches one the values of patience and planning, I've come to learn.
I dunno what the standard price of "panda" plastic is where you live, but here it's about one dollar per foot, and each foot folds out into a one foot by ten foot piece of pvc sheeting that's white on one side, black on the other. With a tape measure and some simple arithmatic you can figure out about how much panda plastic you'll need to cover the entire inside of your cabinet. I know it would be far easier and cheaper to just spray the inside with flat white spray paint; I've chosen panda plastic over paint and have used it in my cabinets for a few reasons - 1) no nasty paint smell and chemicals getting into the air in my apartment, 2) when applied properly in the bottom portion of the cabinet, plastic can be a hedge against any water spilling from a container and leaking out of the cabinet and onto the floor, 3) I dunno what the official word is on this, but I personally see better results when lining my grow boxes/rooms with panda plastic as opposed to white paint. This is my personal opinion based on my own experience and is by no means rooted in any fact that I'm aware of. Of course, if you can afford it, line the inside with mylar to get the most out of your lights.
Growing in soil will alleviate the need for pumps, resivoirs, hoses, etc. that would normally make up a hydroponic system (unless, of course, you're using an automatic watering system), giving you more room to work with inside.
The top portion of these types of cabinets are great as a vegetative/cloning chamber - mount a couple 24" flouresents up top, or a few high-wattage CFL's. It will be important for you to come up with some way of keeping your veg/clone photoperiod (18 hours of light, six hours of darkness) from interfering with the photoperiod in your flowering chamber (12 hours light, 12 hours dark). Maybe use some more panda plastic, or wood or whatever, to enclose the veg chamber and block that additional six hours of light from hitting your beautiful flowering babies, thereby screwing up your flowering cycle.
Come to think of it, where are you going to put your cabinet? The temperature outside the cabinet is going to affect the temperature inside, so an attic or closet is probably right out, as these areas tend to get warmer than open areas, or lower areas of a house. A basement would be ideal but I don't know what your situation is in this respect.
Whatever you decide, I'm sure I speak for everyone when I say I can't wait to see pics of before, during, and after, not only with the construction of your growbox but of the crop as well
And I want to set up a stealth grow room in one of these....
