ARB makes the most tried and true selectable locker out there.
Yukon also has a 30 spline selectable Air locker that is very well built, It is new so it has not been proven.
Auburn has an electric 30 spline locker/limited slip. I have never run one of these so I can't tell you pro's and con's but I can say they are not very popular.
Eaton/detroit also has a 30 spline Elocker. I was always impressed with the way they are manufactured.
Let me know if I can help you out with one of these.
Dustin Sexton 435-640-4437