[Pierre-Marie Baty]

The only memory search tool I can recommand is TSearch, because it's the only one I know (and I wouldn't be surprised if it was the only one existing). It was originally a tool to search for cheats for console games running in emulators (like in UltraHLE, I believe the Zelda cheats were discovered with that tool).

More on topic, I know nothing like the code you posted in the HL engine... I was thinking that all client commands were going either through client commands or impulses, or through usercmd_t's.