I'll need to read the MPE specs to get a full image of how it works, but internally I am using an own message format which allows a little bit more information than just the pure MIDI messages (eg. 256 MIDI channels etc). I think adding MPE support shouldn't be too hard. It's a kind of niche thing right now (apart from Bigwig I don't know any host that supports this yet), but in the future it will become interesting.
But if I understand you correctly, even with the Linnstrument it's only one active note per MIDI channel? If that's the case, my assumption is still correct, I'll just need to add the storage for different channels (which I need to do anyway for any sort of multitimbral sampler).