We have always enjoyed the lamb at Marrakesh in Morocco. In fact, I enjoyed the entire sampler type platter (which included lamb among other things) on many occasions. This particular platter has never appeared on the menu, but was always listed as "manager's special" on the board outside the restaurant. I checked the menu and it is not listed. The platter I usually get is not the one listed on the current menu although the "manager's special" did include couscous, vegetables, lamb and a salad among other items. I may have to pop by there in May and see if it is still and option--really good.
Three Bridges Bar and Grill at Coronado Springs Resort has a nice Lamb dish as well.
All of the above restaurants mentioned have good to very good lamb dishes and we've had them all at one point or another. My wife loves lamb as well.