You mean when using the Find tool? Not at the moment.
The Grep Dir button in my Diff/Merge Toolbar might be of interest. It'll search for a string using the findstr command that's built into Windows and show you which files contain it, along with the matching lines. It's not perfect since they just appear in a text window but I've found it handy when don't want to switch to something else to do the search.
If Agent Ransack lets you run it from the command line then you should be able to integrate it into Opus, if you want to. Shout if you need help.