Rolling Darryls have started arriving from Surly. These are by far the nicest fat bike rims I've ever seen. They are quite light at around 870gms, and fit and finish are top notch. The bead seat is very well defined, and should eliminate any possibility of tire slipping. It may even allow these to be set up tubeless. These are available in quite limited supply right now. I do have one set available for sale, the others have been sold already.
These would make quite an upgrade to any stock Mukluk or Pugsley wheel set. Enjoy.