Hey dude, good luck with your grow. I have a stealth cab with about the same dimensions(29x19x48"). Heres what I'm doing, maybe it will help. the underlined aspects of my grow are some things to think about in your design"
I'm using a 250 watt HPS with a digital ballast (lumnatek), the ballast is housed outside the cab (its got long cables so works great).
To bring up a point someone mentioned before, it looks like a dresser from the front, so i had to secure the drawers so they wouldnt slide out(removed the drawers mounts/backing and just drilled into them from the inside) so i have a door i made on the back with hinges, for access to cab. cuz of this, i had top put some wheels on it, so i added some wood to the bottom to hold the wheel housing.
this lifted my whole dresser by about 7 inches. I then cut out a hole in the bottom of my dresser for my resevoir (im doing DWC hydro) and put a few supporting wiood pieces aross the hole secured to the ends of the wheel supports. this lets the tank drop down about 5-6 inches, giving me that much more room. my light fixture is 7" high, so i basically nulled it.
finally,
since the bottom of my cab has a big hole in it, i just have one big exhaust fan from loewes set up at the top, blowing out that back door (i bought a lil 98 cent vent). its almost identical to this one:
http://www.lowes.com/lowes/lkn?action=productDetail&productId=204319-14-QTR140&lpage=none
this is the one thing i spent some money on, its the quietest and most silent bathroom fan, but it pulls out alot of air. a little wiring is required, but coupled with the hole in the bottom,
i get a nice circular airflow, which has kept the temps at around 80-81 degrees. the inside of the cab is painted flat white, and for the top part that holds the plants over the resevoir,i use a piece of white styrfoam board cut to the EXACT interior dimesons of my cab, so that no light drops down and out that hole in the bottom, lighting up my floor and eliminating the "strealth" aspect of my grow.
so ive got 4 plants going,
using LST method, and so far, so good!
so i hope some of these ideas help with your set-up. the design always evolves as you grow in 'em. good luck!