I came up with an idea recently.
In the MIDI controller settings in an instrument, what if you could make it only receive a signal if the note was between two notes you choose?
What this means is that you can play multiple instruments on the same keyboard on the same channel.
This will also make launchpads work with LMMS. (And I don't think it's too hard to program.)

Thanks for reading!

You can find this here too: https://github.com/LMMS/lmms/issues/1792