I've had dreams of having a Pokemon gym, but some of my Pokemon were ones I created... Anyways, Pokemon would be as follows:
Alakazam--level 32
Ninetales--level 33
Harmonique**--level 40
**=Harmonique is an evolution of Misdreavus--looks like Misdreavus except wearing a blue cloak and with hands similar to Haunter's. It's also in my sig, at least for now.
Building appearance: On the outside it looks like an old theater, with dark purple walls and no windows. The front porch has a triangular roof with glowing pink and blue fluorescent lights on the sides, so people can easily find the gym at night.
Indoor appearance: A solid black door opens to a dark lobby with random, brightly-colored rags hanging from the ceiling and a chandelier that doesn't work. You can, however, see a glowing purple path dotted with multicolor lights. As you open the next door, you enter a horizontal hallway which leads two ways--to the left is a locked door, but if you walk to the right, Harmonique greets you and leads you through the darkness to the gym, with a black battlefield highlighted with blue in the center, and a stage on the opposite end with random junk on it. Benches line both sides of the room, which is as dark as the rest of the building except the battlefield lights up.
**Harmonique also serves as the referee of the battle for the first two Pokemon, then jumps into the battle. Your prize is a TM containing Plasmaspiral, a Ghost attack that does 90 damage and counts as a special attack.