The fact that Dragoneye and Tag and Moose and the other mods haven't posted in this thread says to me that they have some inside info but they're sworn to secrecy. (Yeah, I've noticed your little hints here and there Dragon!)
From what we've seen, it seems that the SS is nearly ready for launch. I thought Fbodfather or some other credible source confirmed that there would be a 'Hi-Po' car released 6/9/12/X months after the initial launch. If the SS is part of the initial launch, then clearly the Hi-Po is not the SS. So when people talk about Camaros, the most prevalent option packages are SS, RS, and Z/28. In many past years RS was strictly a cosmetic/exterior appearance package. So, knowing that the Fifth gen is definitely designed and created with previous generations in mind, it seems likely that they would use the pre-existing designations, instead of a new one. Other designations that were not common across all four previous generations are certainly an option, but some don't even make sense (COPO, for example wouldn't make sense as a badge because it was something totally different, not a trim level/option package).
Putting aside which SS's were faster and which Z/28's were faster, BOTH SS and Z/28 are commonly associated with Camaros across almost all generations. As several folks have said, the SS badge has been extended to many different models across the Chevrolet line-up, from the Cobalt to the Chevelle to the Impala to the Monte Carlo. This is simply not a badge that
uniquely identifies the Camaro.
While there are other Zed cars like the Z24 Cavalier (*faint*), the Z71 package on K-Blazers/Tahoes/Avalanches/Silverados/etc, of course the Z06 and now the ZR1 on the Corvette and I'm sure several others, the Z/28 badge is
uniquely Camaro. If Chevy was to offer a 'Top Dawg', I think the Z/28 is the most likely choice, given what we know today.
Of course it's absolutely possible they're going a completely different direction. But given the other tidbits that have leaked here and there about almost every other detail, I would think if they had some super secret model designation up their sleeve, we would have heard
something about it by now. But then again, maybe that's why the mods haven't posted in this thread yet...