I have a feeling that someone from Leica said it wasn't possible, or rather it would cost almost as much as a MM to do.
If it was possible for a reasonable price, say €2000, I probably would.
I could trade in my M9, and buy a MM, but that would cost me at least €3500 (based on UK prices), and I'm quite attached to my M9 - it's been all over the world with me, and never missed a beat.
- Steve