Ive seen some creative grow cabs made from classic rubber maids and even one out of a cardboard box. Your looking at going Floro's or CFL's if you want stealth, in which case you could go find you a large box like for an old crt tv or tower speakers or something. Line it with some mylar or the shiny backside of some cheap wrapping paper. I would avoid foil as if you are sticking it in a closet, the lack of proper ventilation will warm it up even with cfls, and the metal will promote it to stay in the box. Being cardboard it will be easy to manipulate, and if you f it up, cheap to replace. You can then modify it to best camouflage for your closet. You can even right some bullshit across the front like you used it for moving or something