It's been a while, but I finally put together a new layout for the Q2 that uses the new flip-flop design and exposes an I2C interface. Since the new flip-flop design is smaller, the board is also smaller, coming in at 200mm by 278mm, which is about the size of a US letter sheet of paper (for reference, the previous design was 240x314mm).  It currently uses 987 transistors.  Despite my investigations into making the design faster, I think I'm happy with it as is.  Here's a render of the PCB:

I haven't ordered the board yet since I'm still trying to decide if there are any other changes I want to make. Other I/O options or networking would be especially interesting, though I2C already provides a lot of possibilities for sensors, EEPROM, real-time clocks, etc.