Yes, I identified it several months ago, but I was hoping to at least find one for myself before letting the cat out of the bag potentially ruining any chance of me getting one. Unfortunately, after searching on almost a daily basis for months, nothing turned up.
So drumroll please.........
The M-99 case is actually a Sonia Kashuk brand cosmetic brush holder from Target that sold around 2007-2008 for $9.99!!
Do a google image search for "Sonia Kashuk Cosmetic Brush Holder" and you'll see a picture of it. Some of the images that show up may be from me posting in various makeup forums attempting to find one.

lol I couldn't very well say that I was looking for a Dexter prop so I had to make up some BS about breaking my wife's favorite brush case or something.
Anyway, that's what it is. If anyone finds one, be sure to post pics of it.
Good luck!!