We are using clearcase-mode as part of mf-init, an elisp package written by Marko Kohtala
The package will detect whether a file
being opened is in a VOB directory and in the
affirmative, set up a minor mode.
This one offers some keyboard bindings as well as a pulldown menu.
Some of the commands (such as ccase-edcs)
are also available globally.
The actual files are located in feanor's emacs vob, with the path /emacs/site-lisp/clear*.el.
Also see clearcase-mode for Windows