Looking at the last 1MM visitors to one very consumer-oriented, john q. public type, website, mobile visitors are 7.2%.
Of them, the vast majority are Safari mobile (iphone, ipad, ipod touch) at 6.4% of the total.
Blackberry is 0.4% and the rest are Opera and IE mobile browsers that barely register on the scale.
As long as the full site works well in Safari, I have a hard time justifying doing anything special for mobile, and especially for 0.4% of visitors who can probably get by anyway, though to be honest, I don't really know.
To give some gauge of the types of visitors, it otherwise has pretty standard regular browser numbers.
IE: 50%
FF: 21%
Safari: 13%
Chrome: 9%
(Good to see you to Drastic.)