I'm interested in writing a VST that will only process MIDI, no audio. I've read that at some point JUCE couldn't do it (at least not without the plugin showing as a synth) and I was wondering if there was any changes on that front since then.
In case it did not, if anyone had pointers on how to setup a vst midi processor, I'd be glad to see if there's any way to include that.
Most hosts don't like it when a plugin does MIDI only. You'll struggle with work-arounds to route the signal, if it is recognized at all.
I've done it for AutoTheory ( http://autotheorybymozaic.com/ ) until they decided to change it to a standalone app because it was too tedious to explain how to use it for every different host...