I use Launchy a lot, and can see possibilities for Listary if you want to develop in that direction.
I guess you would need to refocus that side more towards files rather than folders, and provide a way to specify the extensions to use (like .php) and the directories to consider. It would also be useful to be able to prioritise the types of files in the list. Personally for files I would want .php before .jpg for instance.
Just a thought - hope it helps
Mike