OK, I'll try to hammer out a rough plan this weekend at work if it's not too busy. Black will make it easier and cheaper since a high grade of wood won't be needed to make it look good. I'll have to sit down and bust a couple of brain cells figuring the angles
...haven't had to do anything like that in a while. I'm guessing you'll want it about 12" high so you can get those halides off the water a little? Probably use 3/4 plywood. You could use 1x12 lumber, but the plywood will be less likely to warp from the humidity. Since it'll be painted black, a well sanded piece of plywood should look nice. If I may make a suggestion on covering the stand? Particle board won't give you a nice finish. Since this is just a covering and will not bear weight, check into some lauan board. This is very thin plywood...about like raw paneling. It costs no more than particle board and will look much better. Give it a good sanding with a finish sander and prime it with two coats of a good wood primer. Lightly sand the primer just enough to smooth it out good. Then you should be able to paint it and have a nice shiny finish. You could even make some trim by cutting the angle on some lattice board. Trim out around the bottom of the tank with some 1x4's or even 1x6's and you'll have a professional looking job.