humor4funThe UG website lists 120+ for single-sleeved cards. I'm assuming that means 120 comfortably fit while any more will be somewhat snug.
All the reviews I've read say something like "holds a ton of dice", so I don't know exactly how many D6 the box will hold. Since I plan on purchasing some, I'll see if I can perform some tests later with Chessex D6 of various sizes.