Correction. Though the interface at the wheel is basically the same for all 36" frames (in terms of stiffness), there’s still a lot of flex that can happen in a frame. I should have remembered this lesson from my old carbon MUni frame. That’s too long and unrelated to repeat here, but suffice it to say we put tremendous twisting forces into unicycle frames as we pedal, especially uphill. Way more than you might imagine. Add a long handle to the front of your seat or frame, and you increase the torque that can be applied in this twisting.
Therefore, stiffness may be much more a factor than I tossed off the other day, though I’ve yet to do much serious comparing. I have mostly only ridden my own Coker (1st-generation, deluxe) a lot, and other peoples’ 36ers very little.
Based on what I’ve seen and can extrapolate, the V2 frame should be the stiffest by far. This means there should be less flex between the front of your seat or handle and the bearings. This is side-to-side flex we’re talking about. The next-stiffest frame should be the Nimbus (or Hunters), which also have more structure to brace against flexing. After that there are the various steel frames that have been made, which are probably fairly similar and finally the new “alloy” frame on the Big One, which is still an unknown. Surely it is less stiff than the V2 and other multi-leg designs, but beyond that we’ll have to get it out in the field and see for ourselves. It all depends on how beefy the tubing is.
Coker also claims that their new unicycles are quite a bit lighter than the originals. Definitely the new rim will have a lot to do with this, plus general lightness in most of the other parts, I guess. For the moment, I think the tires are the same, but they are developing new ones.
My guess is that the Nimbus frame must be stiffer, but nobody knows this yet. How do you know about the narrower profile? How much narrower? They both look fairly narrow. And both are available with brake mounts.
OUCH! Consider yourself burned. 
Interesting. Did it look like the same exact frame? Apparently Coker is making the V2 frames in-house (in Tennessee), so I’m sure that one was unrelated. It’s possible they “scouted” the job of fabricating the frames in Asia first, which put the idea out there for some high-volume, low-price company to make some knock-offs.
I hope to get my hands on a new Coker soon, and will offer what feedback I can…