"The new firmware 1.196 for the M9 has just been released. If you code appropriately, you will find that there is a new lens code 54-1 (code 54, frame 28/90) which was not there in earlier firmwares. The M9 shows this as a lens "28mm f/1.4" on the LCD screen. Also, this coding will implement a profile coding on the exposed file which compensates for some lens light fall (and maybe other effects)."
Last year lens profiles for a 14mm/3.8 and the already announced 21mm f/3.4 and 50mm f/2.0 lenses were also discovered prior to the official announcement. Unless someone at Leica has a sense of humor, I think it is safe to assume that a new 28mm Summilux-M f/1.4 lens will be announced soon.