Revell made a 65 Impala convertible (several variations of the 65 & 66). AMT released a Scout in 2004 (?) under the "Hot Trucks" series (this is a "2" as well)? I would look at resin casters for some on your list. You could always pick up the crappy MPC/AMT 67 GTO, and sand the emblems off. I know MCW has a photoetch set for the GTO, but not sure about any Tempest badging. I have the lowrider and stock 65 Impala, not sure if I have the convertible (probably wouldn't part with it if I did though). I also have the Foose version. Making a convertible is the easiest modification possible. All you would need is a boot cover.