I think there's a huge chance that these cars will be collectible. Here's a run-down of what I think the most collectible 4th generation Camaros will be in the future (excuse any minor errors as I'm not looking at written stats for my descriptions):
1. By far the most collectible will be the Dick Harrell Editions, they have a widebody kit that is exclusive to the DH edition Camaros and come with the same options ZL1s had PLUS additional options (like a Phase IV engine package). I don't know the exact production details, but so far there are only a few dozen. The real popularity lies in the fact that the widebody does not exist on the aftermarket and it is insanely popular.
2. I believe the next in collectibility would be the phase III ZL1s (followed by other phases) in '69 inspired colors. Colors such as Lemans Blue metallic, Frost Green, and the other rare colors should be popular. The '02 Camaro colored ones such as Bright Rally Red, Onyx Black, and Arctic White will be popular, but not likely as much as the '69 colored ones.
3. The Dale Earnhardt edition Camaros. Several of these are highly limited, for example, in 1995, only 7 Dale Earnhardt Championship Series Camaro Z28s were ever made. Only 3 Dale Earnhardt Signature Series Camaros were made in '99. The GMMG special edition Intimidator SSes should increase in value, but not as much as these insanely limited ones. His name has a lot of value to some people, and even though the non-Intimidator SS cars aren't well-known, they'd still go for a lot on the auction block with proper paperwork and authentification.
4. Berger Camaros in unusual colors. Berger did not make too many Camaros in full-out custom colors, most remained the factory stock colors. The yellow and hugger orange ones will remain popular and exclusive along with the 1 of 1 in the Dupont Chromalusion color and several others. Hot Rod Magazine Camaros can be lumped in this group as well. One was made for each year the Camaro was produced (36 total made -- 1 was a test car). For example, #1974 represents the 1974 Camaro.
5. Callaway C8s. Callaway C8s aren't popular with the Camaro people right now, but they may be in the future. The name is fairly well known, the car just isn't that popular. The fact that no production numbers have been published (that I know of) probably hurts their value the most. The Camaros with just the SNATs will probably increase in value as well.
6. Factory special editions like pace car replicas, anniversary editions and of course the rare optioned Camaros. The 1LE option is already popular since it was like ordering a Camaro for the race track and I believe the F-1 appearance package will increase the value of certain cars that actually have received it. (I've only seen two in person). The one pictured below is an export model of the F-1 (note the mirrors and sidemarkers).
7. Hendrick (hard to identify from the outside if you don't read the floormats), Tom Henry (essentially the same thing as Berger Camaros but far less known), Mecham Z29R, and whoever made the ZR28 may become popular in the future, but the production history is pretty much unknown and nobody knows what these are anymore ESPECIALLY wacky special editions like the Granetelli Signature Series Camaro(s), the ZR28, etc.