RM005 but now it's the RM010 in Ti. No SS models AFAIK.
basically the same watch, but 010 is a bit larger, and has a more skeletonized movement.
005 offers 100m water resistance (I believe it is the highest resistance other than the newer, round-shaped diver watches), 010 offers 50m.
AFAIK there are no basic models in the rm004 case.
Models you could consider basic are RM005 (no longer produced), RM010, RM023 & RM028 (any deliveries yet?)