have you looked at gnome-do? its the gnome answer to spotlight / quicksilver, you invoke it, start typing and it lists matches in a somewhat similiar manner.
The current release in ubuntu is somewhat patchy, but I really hope they work hard on it and enable it by default in the next release, its an awesomely useful application that has at times replaced
1. the menu bars completely,
2. a lot of trivial stuff done in the shell (copying / findings files)
3. the awesomebar for firefox
4. navigational controls (alt+tab for window focus)