I was under the impression that these harmonicas were available in lots of keys, even minor keys. Jia-Yi has held as many as four or five in his hands, and for more complicated music, lays them out and picks up the ones he needs.
Why bother? Chords, man! He can harmonize any melody with the right choice of harmonicas, and play really fancy tunes by picking the ones he needs to play a certain scale or transposition. Cool.
Huang (and possibly others) sells a set of C/C# harmonicas that can be played like a chromatic, but with two mouthpieces and no button. If anyone has ever seen a Tombo S50 chromatic, it's the same principle. I'd consider switching if it were better made; the tone is tinny and thin. But I am able to get around on it almost as easily as a button chrom.
Tom