There are some but very few. My dealer currently has ~110 X drive 3's in stock and 10 RWD 3's.
Better premiums on the X and it's an easy sell. Most people who really want things like RWD and manuals will be more likely to order the car exactly how they wanted. Also good luck finding a car with packages like DHP, most people don't care about how their suspension feels they want leather and safety cameras.
Current: '15 M235i Vert
Previous: '13 335i, '08 TL-S, '00 Corvette