My $.02 worth.
I would knock it down to 3 or 4 buttons (like mentioned above) maybe stagger with 2 on top, 1 on bottom.
O O O O
O or O
But, I HIGHLY recommend, putting it in carboard, or on a seperate piece of MDF/Plywood, as a "mock up" first.
Then mount the controls, and play with it for a while, and see what you would change. After you are comfortable w/ the setup, you can make a "Final Draft" and add artwork, and what-not.
The general consensus with this method, is that no matter how well it is laid out, you won't know if it "feels" good, till you try it for awhile.
Good Luck!
If you type 2P CP in the search, you should find many designs.