We have 85 more 737 (mixed 700 and 800) on order currently, the first three of that lot are delivered (should be 6 by now, but the Boeing strike...) and they are most certainly CAT IIIb approved. Works like a charm to be honest, much smoother approach and perfect rollout, even with close to the limit crosswind.
Don't know if the following stuff is new, it is certainly for me as we switched from -300s to 8 year old -700s and now brand new ones. Added to CAT IIIb they all allow IAN approaches which makes non precision approaches a non issue as you fly them with exactly the same procedures as you do fly an ILS. GLS (or GBAS) capability is another feature, but since airports with working GLS approaches are so rare i didn't have a chance to try it in the real world yet. The vertical situation display is a gimmick and quite usefull in mountainous terrain, but it is to be used situational at best (need bigger screens for that).