It's not in there, doesn't mean it doesn't exist
Apple has a lot of things like that... pie chart progress bar for Safari, debug menus, show hidden apps as faded icons in the dock, etc. Lots of good stuff under the hood.
Anyway, type this into the terminal, log out, and come back in to a better dock:
defaults write com.apple.dock no-glass -boolean YES
I'm assuming you know how to revert if needed.