It is possible however to bolt in just about any dash you want if you have the skill. Entails cutting out the old, temporarily mount the new dash and fab brackets to bolt it into place. Easy, no, but it is possible. There is a guy in our Camaro club (don't have pictures here) with a '69 Dynacorn Camaro 'vert with a full interior out of a mid-late '90's Firebird. Also found this example of a modern GTO dash in a '69.
http://www.pro-touring.com/threads/8...h-in-first-gen