MIDI 2.0 has attributes in note-on messages. Attribute type 0x3 gives you 7 bits for a note in semitones and 9 bits for a fractional part of a semitone, so a resolution of around 0.2 cents.
That's effectively just per-note pitch bend -- which is great to have, but it's still kind of problematic to only have 128 unique notes you can individually toggle on and off or otherwise control on keyboards that have more than 128 keys.
It's possible to work around the 7 bit limit, but it's awkward.
