Thanks for the responses so far. i'll look up the clone doctor code...however i cannot send this codebase to 3rd parties.
the second approach, using dumper, looks like will only identify duplicated but individual lines of code across the scripts...which would be just as easy to do using
cat *.php | sort | uniq -c
i'll keep thinking about it too..and will post any gems. a brute force reducing sliding window between two scripts is possible but probably blow out to hours/days of running time for the 40 or so script pair combinations.
the hardest line to type correctly is: stty erase ^H