IMHO the 1M will follow the path of the BMW E46 M3 CSL: low production (1400 cars), limited in time (MY2004), powerful special version, only two colors (SGM + BSM), special 19" BBS rims, etc.: these hold well their value.
Even the controversial BMW Z1 is still doing well in resale:
"The first example of the Z1 was released by BMW to the press in 1986 and later officially presented at the 1987 Frankfurt Motor Show. Initial demand was so fierce that BMW had 5,000 orders before production began. However, demand dropped significantly around 1988 and BMW ended production in 1991. There is speculation that the drop in demand was due to the early inflated demand from speculative investors. In 1988, however, BMW was quoted as saying that they had 35,000 orders for the Z1. [...] BMW only produced 8,000 Z1 models.
[...]
New Z1 vehicles sold new for 83,000 to 89,000 DM or between €42,000 and €45,500. As of 2001, used BMW Z1 vehicles were selling for between FF125,000 and 250,000 (between €19,000 and €38,000) in France including a 19.6% VAT. One example fetched just over £20,000 at Bonham's 2004 Olympia auction. In 2006, cars could be bought in France for a price between €25,000 and €30,000 the upper being reach for cars in perfect condition with low mileage."
(source:
http://en.wikipedia.org/wiki/BMW_Z1)