Pics
The case shown in this link is typical of an O'Neil case.
http://forums.azbilliards.com/showthread.php?t=218458
I believe they come in configurations from a 1x1 all the way up to the dealer case which is a 12x12.
I've purchased 2x2's, 2x4's, 4x8's, 6x6's, 12x12 dealer case, as well as a 20 cavity dealer case that only holds butts. Some of my cases were made extra long and they are available with or without a storage area.
Interiors are generally black but I have one he made in green as well as a special order he made for me with a white interior.
Some people claim the older cases were nicer, but I have both new and old O'Neil cases and can't see any difference in any aspect of them. A well-known dealer in high-end cues recently told me these were one of the best cases in which to safely store cues and that they should be stored on end with butts and tips down.
I find Mark easy to work with but he has very few if any cases ready to ship. Most are made to order and dependent upon which wood boxes he has on hand from his supplier. I believe he works alone but may have another helper in the shop. I'm not sure.
He generally gets a case to me in a couple of weeks or sometimes longer if he is waiting on wood boxes to be delivered.