The cp latches can be bought from TwistedQuarter. Just look around on the site, I don't remember where they are (cabinet hardware?).
The top back doors are fairly easy to manufacture. Go to HD and get a 36 x 24 sheet of 1/2" plywood and cut it down. Then either use a router or a table saw and cut the inset on the bottom. One quick hole for the lock and you are done. They take about an hour and that includes the 1/2 hour trip to HD.