Nirsof's tools are, for the most part, small and portable.
Being portable makes it kind of hard to provide an updater that can keep track of their whereabouts on people's drives.
About the only ways for an updater to know what's there is to:
1) Have the programs leave a current installed directory key in registry somewhere every time they're run - but who's to say the person won't move them between last program run and running the updater?
2) Have the updater scan all your hard drives every time it's run to find them.
3) Have the updater ask the user to input the path of every one of the programs, (or group folder).