Take a look at the Command-T plugin:
https://wincent.com/products/command-t
Here's the description from the developer:
The Command-T plug-in for VIM provides an extremely fast,
intuitive mechanism for opening files with a minimal number
of keystrokes. It's named "Command-T" because it is inspired
by the "Go to File" window bound to Command-T in TextMate.
Files are selected by typing characters that appear in their
paths, and are ordered by an algorithm which knows that
characters that appear in certain locations (for example,
immediately after a path separator) should be given more weight.
As you browse, files are presented in a flattened list, with full pathnames relative to the current directory:
Surface.java
TextureChooser.java
Tools.java
demos/Arcs_Curves/Arcs.java
demos/Arcs_Curves/BezierAnim.java
demos/Arcs_Curves/Curves.java
demos/Arcs_Curves/Ellipses.java
demos/Clipping/Areas.java
demos/Clipping/ClipAnim.java
demos/Clipping/Intersection.java
demos/Clipping/Text.java
demos/Colors/BullsEye.java
demos/Colors/ColorConvert.java
demos/Colors/Rotator3D.java
demos/Composite/ACimages.java
demos/Composite/ACrules.java
To narrow the list of files, type characters from anywhere in the pathname. For example, dcb or bul are enough to specify demos/Colors/BullsEye.java.
Once you've typed enough of the pathname to find the file you want, just hit Enter to load it. (You don't have to get all the way to a single file; once you're close, you can use the arrow keys to select the one you want.)
Anyway, it's not exactly what you described, but it might be exactly what you want. :-)