No, his method would work.
You can use his suggested search to make a view that shows ALL STACKED TRACKS regardless of Collapsed/Expanded status. Then, you can just switch to that view, and search using the regular search widget. You could, modify that search to just show all files (that's the ~d=a part, but you'll have to tweak it to hide things like Deleted Items, removable media, Optical disc entries, and other stuff first).
You might be able to do something like [Stack Top]=-1 || [Stack Top]=0 to search all files, stacked or not, combined with the ~d=a modifier. I'm not sure, I'd have to try it out to see. (EDIT: I think you might need to do it a different way, actually. Because that would still exclude files where [Stack Top] was a particular key, which is true for the members of the stacks... In any case, if you just use ~d=a, and then modify the search to exclude the extremely ugly, you should be able to get what you want.)
Searching using the search box always searches the contents of the currently selected view, ergo, it'll search everything.
An easier method (and what I've used before when I need to check for Stacked files on occasion) is switch to your All Media View (you should really have an all-media view, as you're obviously an advanced user), then:
Control-A
Right Click > Stacks > Expand
Search
When you're done:
Control-A
Right Click > Stacks > Collapse