<p>Does anyone have tools or experience with code coverage for PL/SQL. I believe this is possible using DBMS_PROFILER?</p>

Not sure if this is quite what you're after, but in 10g onwards there's a tool to do static PL/SQL code analysis.
Info here...
http://www.psoug.org/reference/plsql_warnings.html
Note that it can be enabled at either session or database level.
In my experience it's thrown up quite a few false negatives so far.