If you put a five(?)-octave keyboard on an accordion, meaning that you had to rest it on your knee, play it flat and hold your bellows arm out in front of you, you'd have something like a harmoniflute. When John was in Chorlton he pointed out that it's more portable than a harmonium, although since he'd brought a harmonium* as well I'm not sure how much weight to give to that explanation. I suspect it's a horses/courses compatibility issue.

*Strictly speaking, an American organ.