One of my few gripes with the EOS M has been ergonomics - I find it difficult to hold, as the "grip" they put on the front is inadequate. I thought they could have put a larger grip on the front, without increasing the Z-depth of the camera at all, similar to how Panasonic does it with the GX7. Once you mount a lens - any lens - onto the camera, the added depth becomes moot anyway.
Richard Franiec, who has designed camera grips in the past, has announced a grip for the EOS M. I ordered one - should be arriving late November. It was under $40 US. It looks like it will improve ergonomics somewhat with the standard EF-M mount lenses, and will greatly help ergonomics for those who use it with larger EF lenses as well.
I am not affiliated, I just ordered one. Hopefully someone else will find this useful as well. First saw this on digilloyd:http://diglloyd.com/blog/2013/20131029_2-RichardFraniec-grip-for-EOSM.html