Fair point. Sorry about that. Let's move on.
I've just tried the keyb zone lru object, and it does appear to do exactly what I wanted in fact!
Sorry for wasting everyone's time.
...Having said that, there is one other thing I'd like that patch to be able to do, and I don't know if it's currently possible at the object level.
It would be great it there was a third gate object that stayed high as long as more than one note is held. With that, you could do all those classic mono-legato/triggered portamento/glide effects that pair so well with the lru behaviour.
Having looked at the keyb zone lru object code, it looks like it's being passed data about notes, gates and velocities from a lower-level function (which I think it what you were saying, earlier, @thetechnobear).
That being the case, I guess it's not currently possible to get the count of currently-pressed notes in object code, so a gate outlet to trigger slew/portamento on legato notes also isn't possible. Maybe that's something that could be added later.