REST-based controller using HEAD to test for exist?/status?

I'd like to add an API to my REST-based controller that indicates the existence of a resource (and maybe other status like the last time it was updated.)

If I understand REST correctly, this seems like a natural use of http's HEAD method. I should be able to just add route for :conditions => {:method => :head} param, and implement a status or exist? method to my controller.

Why isn't this generated when I create my scaffold-resource?

How do others solve this problem? Do you just test for head? in your show method?

I'm curious to know the best practice.