Is there a version of the Handy Board that uses the 68HC12 chip?
No, there is no 68HC12 version of the Handy Board. If I revise the HB, I will move up to a chip with substantially more horsepower and a flat architecture for expanded memory; e.g., the 68332. While the HC12 is a wonderful chip — and it certainly would make sense to use it if starting from scratch — the improvement from HC11 to HC12 is not great enough to warrant a re-design.