MOTM

Not meaning to rain on anyone's parade, but syncing the frequency of an LFO
to MIDI clocks is probably only about half of the battle you're trying to
fight. The other half is syncing the phase of the LFO to measures. If you
don't have phase sync also, the LFO's phase will vary with respect to the
rest of the music every time you start/restart your sequencer. Whether or
not this is an issue depends on your needs, of course, but typically people
want phase sync when they want "tempo-synced LFOs." So part of this
hypothetical LFO would have to include parsing the other MIDI real-time
commands (in addition to clock) and acting accordingly.

Then, of course, you have to decide whether you always want your various
wave shapes to have the same phase relationship to the beginnings of
measures, and if not, how to control this relationship.

--Adam
(author of several plug-ins with tempo-synced LFOs)