Why would you need to cut the height in half? What size tank you planning to use it for?
Check out a Lowe's or Home Depot ...if you have exact measurements, most will cut plywood to size for you [probably cut the hole in the front one for the door too]. I recommend you use 1/2" or thinner plywood. Buy a kitchen cabinet door that will fit over the hole, and hinges, screws and knob for it too. Avoid laminate, it is very difficult to work with if you don't have the skills. Use a sturdy paint instead. Get some liquid nails [quick-grab is good when working by yourself] to glue panels to back, front, and sides. Attach door, sand smooth and paint.
I'm obviously over-simplifying, but I can be more specific if need be. If the stand is wobbly, shore-it-up before attaching sides [cladding.] Don't forget the bottom shelf first.
Outlets are easy ...buy a cheap 6 outlet strip, and mount to the inside with 2 screws [unless you are confident with your electrical wiring...] and a pack of wooden shims to level it.