What do you expect to do with a replay search? You'll find 10 to 100 matching replays. Should the search print dates, players, ...? For each hit, there is not that much room to preview that hit. What are your use cases?
In a networking game, the client doesn't know the map filename. The level selector sends the level file to the server as raw bytes without a filename, and the server distributes that. When the client saves the replay after the match, the client still doesn't know the selector's map filename and can't use it (unlike in singleplayer) to generate a replay filename.
I've resorted to the date. Do you want the level selection to transmit the filename instead?
It's also conceivable to let the receiving client guess a filename from the level title or from looking through his own level tree, but that's dubious design. Never does the current Lix 0.10.26 guess level filenames.
Yes, external search tools can help. How exactly do they help you? For what do you search? Only ever for a level title? Or do you search for particular replays in a more specific way?
-- Simon