I saw a nice brown leather classic case for the M5 from canon ... Somewhere ... It was a half-case reminiscent of the "ever-ready" cases of the rangefinder era.
They call it a "body jacket" and it appears to be available in black and brown.
The brown one cane be seen on Andy Westlake's Preview
M, 6D, 7D, 1Ds II, G10, IV-Sb, 17-40, 24-105, 70-200 2.8 IS, 85/1.2 II, 50 1.8 II, 40, EF M 18-55, EF M 22 ...