fwiw, i'm achieving quite satisfying results driving MIDI out from a 1024 Hz RTC thread, with external hardware locking steadily onto the output MIDI clock stream, even at tempi up to 240 bpm. MIDI out jitter is about the audio block size at max. DSP load (~1.3 ms) during audio processing cycles, a fraction of a millisecond for the difference between 1024 Hz and the wanted MIDI clock frequency otherwise; however this seems to be no problem for the hardware attached (a fairly recent synthesizer and infrequently an aging cheap drum machine). at lower RTC frequencies, the jitter effect on the MIDI h/w becomes noticeable (erratic rubato) but it still locks on. thus, i must disagree with your 'no way'.