There are two motivations for this question: I'm trying to distill the essence of what tonality in common-practice music really means, and I'd like as a compositional resource to port some aspects of common-practice sound to music written in non-diatonic scales.
What would it mean to have "tonality" in any key but a major or minor scale? I understand that tonality involves hierarchy, so whole-tone and other completely symmetric sets aren't great for expressing tonal idioms, but what about the hexatonic, pentatonic, or acoustic scale? Would it simply be a matter of using the usual tonal relationships but adding a few sharps/flats, or could you devise something that is both tonal and substantially different from diatonic tonality? For instance, could one have a system of tonality that revolved around a relationship other than tonic-dominant? Could one devise prolongational structures or music susceptible to Schenkerian-reductions that create completely different assumptions about tonal relationships?