[sfx1999]

I found a function that looks like it would work.

Declaration (game_shared/multiplay_gamerules.h):

virtual bool ClientConnected( edict_t *pEntity, const char *pszName, const char *pszAddress, char *reject, int maxrejectlen );

Implementation (game_shared/multplay_gamerules.cpp):

bool CMultiplayRules::ClientConnected( edict_t *pEntity, const char *pszName, const char *pszAddress, char *reject, int maxrejectlen )
   {
     GetVoiceGameMgr()->ClientConnected( pEntity );
     return true;
   }

In gamerules.h, it stated it was called when a player connects, but isn't spawned.