Rational Team Concert for System z (currently in 2.0 Beta 3) includes a technical preview of a contextual search facility that not only searches source in the SCM but actually performs some really good guessing from the work item description (or other search terms you provide) about which source files you should start looking in. Note that the System z version is simply a superset of Team concert that supports the z/OS and Linux on system z platforms in addition to all of the core Team Concert platforms. It also includes extensions that support development and build of System z applications. Even if you have no need for the latter, you can still do everything else you can with RTC so you might want to consider this upgrade if only to take advantage of the contextual search feature.
BTW, we're very interested in feedback about the contextual search feature to see if we should consider graduating it to product status.