In additon turning on/off toolbars dependening on filetype, an option to do this with buttons within a toolbar would be fine (like show-thumbnailsize-buttons behave).
As in tied to Content Types, based on the files in the folder?
You could use scripting to set/remove a variable on folder change when a Content Type format is in use (or just have the script look at which files are in the folder), and have the buttons test the variable.
A more automatic way could be useful, I agree. Although don't forget you can have more than one toolbar on the same row; they don't need to be on separate lines.
You can also already do this (without needing any scripting/variables) based on the selected files, if that helps. For example, a button that only appears when JPEG files are selected.
Which option is this? Seems I have overseen it...
@hidenosel is the main one.