Ah great - it looks like someone has done it: produced a QuickSilver-like product for mobile phones. Qix "ugments the phone interface by automatically presenting candidates to the user based on the data he or she inputs. The information used to generate candidates is sourced from a suite of different data stores on the phone".
Where can I get a copy of this? The basic way in which I've interacted with a mobile phone - press a menu key, get options, or type in a number - hasn't changed since my first mobile back in 1998/1999 (I was a late developer in mobile terms, and held off getting one for as long as possible). Just as QuickSilver completely changed the way I use my Mac, I'm looking forward to being able to hunt through the increasing amounts of Stuff on my phone in more efficient ways.
I see LifeBlog as a prototype for this kind of thing: it does an excellent job of bringing together lots of sources of data and presenting them in a unified fashion, but it's about *reading*. Qix looks like it might go further than this, and let you not just read Stuff on your phone, but Do Things.