I want to be perfectly clear. This thread is not intended to insult your opinion of which trim is the top trim or whether such a trim exists. This thread is only seeking clarification between speculation and fact.
From what I understand, the source of the Z28 presumption comes from the below sources.
• Since their used to be a Z28, their must be one now. Traditionally that Z28, being a higher RPO code, is a higher performance trim than the SS. In response to this, I must remind all readers that tradition is not a determinant of future events. There used to be a bunch of Z cars, including the Cavalier and Lumina, that no longer exist in production and apparently will never return. This is a reasonable speculation because the Camaro is a car with a strong tradition, and strong traditions tend to be followed more than weak ones, like the lacking following of the Z24.
• The SS is the one we know about, so the Z28 is the one we don't know about. We don't know about it because it will come out when the convertible does. I cannot cite the source from memory, but I do recall something of a special Camaro coming out a year after production. Maybe there is a future performace Camaro, but there is not enough evidence to suggest it is a Z28. With the recent ZR1 Corvette, I would lean toward a performance ZL1 Camaro because that would better fit the Chevy lineup. If they called the high-performance Camaro a Z28, then Chevrolet would be obligated to make future high-performance Camaros Z28s instead of ZL1s, a clear violation of tradition, which we agreed was important to the Camaro in the previous argument.
• Competing companies have a high-performance trim, so the Z28 must fulfill that role. The GT500 is not the only special Mustang, and the Daytona is not the only special Charger. As a result, having one prime Camaro to match all of the special editions is nonsense. Chevrolet has no need to compete with ridiculously priced vehicles that get very little attention outside of the enthusiast realm. If you went down the street asking people not as interested in cars as us whether they know who makes the GT500, very few would know. The Z28 and the SS nameplates are both far better known. If GM were to match the GT500 trim exactly, then GM would match it with an equally dominant trim, like the ZL1. This, too, is speculation.
• Magazines have been printing that the Z28 is going to be amazing so it must be true. If there is a Z28, then it will be amazing, so it is true; however, the same magazines have claimed that the Camaro will have the current pre-production headlights as production, that the Camaro will have 2 V8s at launch, and that they have better insiders than fbodfather, which we all know is a bold-faced lie.
• Since the Camaro tends to come in multiple V8s, there must be an alternative to the speculated SS LS3 or L76, which must have forced induction, and further must be called the Z28. This is ridiculous. I mean no offense to those who believe this, but every part of this sentence is potentially false. We have no confirmation of the primary V8 engine, nor do we have evidence that GM is working on a forced induction platform for the Zeta, at least to my knowledge—correct me if I'm wrong.
• Z28 is the highest RPO code when compared to RS (Z26) and SS (Z27). This is true for traditionally ordering a Camaro. I don't know if this ever changed.
• The Z28 has not always been the highest tier when compared to the ZL1 and the fourth generation SS. This directly contradicts the idea that Z28 is superior to SS or ZL1.