> There are 342 occurrences of '\\\\([^?]' in CC Mode.  Most of these can
 > surely be replaced by "\\(?:", but not all, by a long way.  This change
 > will be fun.

Years ago I wrote the attached that might help you in this regard (load
it and do 'turn-on-regexp-lock-mode').  If you move point before the "("
of a "\\(" it should give you the appropriate nesting.

martin