Some. Many B1900Ds have a recirculating flush toilet at the rear of the cabin. No washbasin, only some kind of waterless hand cleaner.
Must be an airline option. The split sliding doors to the lav can be seen at the end of the cabin in this photo. I'm sure someone must have submitted a picture of the B1900 lav to a.net, but I've never come across one yet.
"* NWA DC-9s - bucket on the floor in front of the tail exit."
Umm, that thing in front of the tail exit is the jumpseat. And the only buckets I know of is the one for the giultine used to stop crap like that!
Flying an aeroplane with only a single propeller to keep you in the air. Can you imagine that? -Capt. Picard
Interesting, because I remember is the BBC "Airport" They had an episode on a QF 744 and they said it is the only airline in the world to have a window (that can be view not one of those that have being blocked).
Also interesting is that the window is electronically controlled (I think it is located higher then other windows (compared to when you sit down). Therefore I think it uses reflection technology to project the views outside on the window. Before you lock the toilet door the window actually freezes (it becomes foggy and blurry) After you lock it the projection will come on
Have read about Royal Brunei. They have a very very spacious toilet in the first class with carpet and the toilet itself is hidden under a leather bench. Furthermore you have new towels for every "user".