I met chromatic players with specially-tuned chromatics too. Brendan Power is an obvious example, but I met a guy working with harmonica trios and quartets using a chromatic harp designed to play a major 6th chord up and down the instrument. Pretty big-band and cool.
It seems to me that much of what I thought about special tunings is wrong. First, they’re not new. Second, they’re much more widely used than I suspected.
One guy I met at SPAH proposed that you might eventually have a differently-tuned harp in your kit for every song you play. Well, why not, especially if the harp takes over a role in the band that involves more harmony (as opposed to more lead)? One thing those special tunings are really good for is getting all the chords you can’t get otherwise. And they’re a lot easier to haul around (and more versatile) than a chord harp.