I was thinking about M-32 in my earlier comments about black. Black is the normal color of the M-37C, but the alternative M-32 is REALLY black and especially cool looking, as shown here:
While we’re on alternatives, I thought I should mention the delightful little Yamaha P-25F, currrently at $51 US from Amazon with free shipping for Prime members. On many tunes it requires some transposition and improvisation, but that’s not such a bad thing. My P-25F (or P-25E) is always out on my desk. It’s so easy to pick up and pack anywhere.