I've looked through the documentation and I'm fairly sure there's no way to do this yet.
There should be a way to search for all occurrences of players and all occurrences of certain blocks within a replay file. This would be helpful for using long replay files where it's hard to find the action and finding raids on factions servers. For players it would list where the players where at what time and for blocks it would say what chunks have those blocks, how many of those blocks were in that chunk and at what time the chunk was loaded.
