If I were to get back into the Leica M system today, it would be with a CMOS camera: M240 or newer. If price is a concern, inquire about demo or refurbished units which come with a Leica warranty.
I enjoyed M9 when I had it, but it was always beta-quality, and I never felt the sensor was anything particularly special, save that it's dynamic range was poor, and in that sense I guess it's output did resemble slide film a little bit. But why not just buy film-effect software or a Fujifilm camera if you want film-like output?