A couple of points-
The reason there is a difference between LR and ULR- there are more lavs on the ULR, so it actually gets less crowded while pax wait. On an LR going to say, LHR or CDG, the lines actually get quite long, (only 3 toilets for almost as many pax not 5) hence the fwd lav is left 'open' for pax to use UNTIL one of the cockpit crew feel the call of nature. That is when the 'VIP Rope' comes into the equation. (Airbus' name for it, not EK's- their manual takes a lot of the original AB terms)
On ULR flights funnily enough the lavs seems to get less usage (prob beause everyone is out to it sleeping, whereas on Euro/UK flights lots of them stay awake to enjoy some bevvies and as many movies as they can fit in)
Aside from seats/fuel/weight issue you'll find the CRC is where it is because it allowed extra pallets of freight where the factory standard CRC would be. That info was direct from TC in a flight global article about a year ago...
Lav 'policy' (at least on the CC side) has been in place as long as I have flown on A380, coming up on just about 3 years, actually!! It's just not as rigidly followed on all flights since on the day (at least as I was told) it's up to the skipper's discretion. If s/he wants the rope up for the whole time, they can ask. It's just not recommended since it clogs up the front of the plane to have one lav out of use. (Pun not intended!!
)
So technically, yes there is a dedicated crew toilet on ULR flights, since the crew are the only ones using it. But it's not inside any crew rest area, which I suppose is the technical definition of a crew-only toilet...?
Edit:
Article
here
Clark says the decision to put the cabin-crew rest on the main deck was basically to preserve cargo capacity. "There is not much volume on the bottom deck," he says, adding that cargo can account for up to 20% of the airline's overall income.
The airline is due to take its first "medium-range" configured A380s next year that will differ mainly in that the crew rest zone will be removed and replaced with 28 economy seats, says Clark. These will be used on sectors of less than 12h.
From 2010, Emirates will introduce A380s with a two-class cabin layout seating 604 passengers - 60 business and 544 economy. These will be used on "regional" routes of up to 6h from Dubai.
Hmm bit late on those 2-class then!!