It's probably the most compact way of doing what you want.
The only thing is that you try an include, and see if it fails, whereas I would probably first check if the file exists before I try to include it.
Just my way of doing things.
Altough it might be a good idea to start some sort of look-up file where the filenames and their locations are stored so you can include the "locations.php" file at the top of each page, which the tells you where each include file is.
That's a bit more maintenance, but it'll save you the trouble of trying several different locations in each script.