Here's my idea: A utility that scans a set of (user configurable) directories, to find executables (.exe) for which there is no matching start menu item.
Bonus feature: Show the list with checkboxes and offer ability to create shortcuts for the items in a special subdirectory of start menu.
This utility would be useful to find programs that aren't on your start menu for some reason, maybe because they were left over from an uninstall, or maybe one is scanning their own portable app directory that one would like to have added to the start menu.
Some subtleties to this app:
1. You will have to be smart about scanning and caching the start menu shortcuts. That is, you will have to FIRST scan the MULTIPLE start menu folders, and parse all shortcuts found, and cache the paths in a datastructure that you can do fast string lookup on.
2. And only then start scanning the directories and looking up paths.