I haven't heard anything about GM saying anything about a Z28.
All we've got here are supposed test mules...
If you're worried about a Z coming out soon after an SS, why not lease? You'd only be locked in or a couple years and you could enjoy both an SS and Z28.
1998 Bright Purple Metallic Camaro: 1 of 336
2012 Carbon Flash Metallic SS Convertible A6: 1 of 1103