I could not successfully override locate-domination-stop-dir-regexp via .emacs because vc-find-root restores the default value.

STR:
override locate-dominating-stop-dir-regexp in .emacs with:
         (setq locate-dominating-stop-dir-regexp "\\`\\(?:/uufs/chpc.utah.edu/common/home/[^\\/]+/\\|~/\\)\\'")

edebug-defun locate-dominating-file
stop at string-match, note value of locate-dominating-stop-dir-regexp
continue to next call to string-match (for a different dominating file)
re-check value of locate-dominating-stop-dir-regexp

You will find that for calls from vc-find-root the value of
locate-dominating-stop-dir-regexp will be the default (from files.el) as
opposed to the value in the .emacs setq

I maintain that locate-dominating-stop-dir-regexp might be better served
as an extensible list though others believe concatenating regexp after
regexp is the way to go.

An exchange on the google gnu.emacs.help forum can be found here: https://groups.google.com/forum/#!topic/gnu.emacs.help/wec_aPpUmqg <https://groups.google.com/forum/#!topic/gnu.emacs.help/wec_aPpUmqg>

Thanks,
rjs