Well, it seems that I had some momentum after finishing the FreqTalk synth, and I had a spare Diecimila laying around, and so I slammed this together over the past few days:
FreqClock driving the FreqTalk:
Splash screen and user interface detail:
This box is just a MIDI clock/sync generator. The unit powers up to a default BPM of 120, and the knob lets you cue up any BPM from 40 to 156 (arbitrary limits, based on what I thought I'd use). When the cued BPM does not equal the current active BPM, the ACCEPT button illuminates.
The START / CONTINUE / STOP buttons issue MIDI sequence control commands of the same names and display text accordingly on the LCD. The RGB LED above the START button flashes red on the beat if the START / CONTINUE / STOP functions aren't active. When START is pressed, the LED continues to flash on the quarter note beat, but indicates the downbeat by flashing green, and beats 2, 3, and 4 flash blue.
The HOLD button allows you to suspend clock output and the LED above it flashes red and the LCD displays "HELD".
Concise, useful, and needed only 260 lines of code (including the NewSoftSerial library to drive the LCD).
OK, what's next?... :)