The terminology appears to have evolved as follows:
reverse camber: The ski has a continuous curve with no (or virtually no) flat spot under the foot. Examples: Praxis, Spatula
rockered: The ski has a flat spot underfoot but has relatively early & dramatic tip/tail rise when compared with a conventional tip/tail. Look at the shape of a modern play kayak (a significant discussion of convergent evolution is possible...). Examples: Pontoon, ARG, DP Lotus, Hellbent
It seems rockered skis generally have some amount of sidecut to facilitate use on groomers, cat tracks, etc. I think it is fair to say that there is a whole lot of overlap between most reverse camber & rockered skis in intended use for powder & soft snow. The Pontoon is hardly a park ski...
I have a pair of 195 cm Rossignol Super-7s, which are a powder ski with 117 mm waist and rocker in both tip and tail. It's basically a longer, slightly wider S7 with a lot of added metal to stiffen it up and fix the S7's skittishness in crud. The rocker works very nicely on those skis in that it gives them much better floatation and maneuverability than otherwise similar conventional skis, while retaining most of the stability benefits of a long, stiff ski.
I've also skied the new Volkl Kendo and own the older (non-rockered) Kendo, both in 184 cm. I think that the rocker is less beneficial on that ski, in that it detracts noticeably from turn initiation on hardpack/ice but doesn't help all that much in the deep stuff. I actually prefer the original overall, and particularly in that it responds better when driven hard through intermediate-radius turns. Of course, part of that could be due to tune as I tune my own Kendos with 1/3 bevels and no detuning within the contact points.
Tip rocker in particular has been around for a long time: I have a pair of 222 cm Salomon DH skis (reputedly made by Atomic) from ~1996, and a pair of 210 cm Atomic SGs from ~2000 [*]. Both were built with intentionally splayed tips, which today would be described as "tip rocker". My understanding is that SG/DH skis are (sometimes) built that way both to help break suction in warm snow and to shift the running surface slightly aft when the ski is run flat (the rockered portions only engage when you bring the ski up on edge). The Atomic SGs also have tapered sidecut (increased sidecut radius) in the last few cambered inches of the tail, such that the the running surface extends further back when flat than when on edge. This is sort of the opposite of tail rocker.
[*] The Salomons have a ~52m sidecut radius and the Atomics have ~40m, which means they're both quite close to *current* SG and DH skis in overall geometry.