He has 24 HRs and 39 SBs in 99 games so far. I called up all the seasons with 20+ HRs and 35+ SBs using the Lee Sinins "Complete Baseball Encyclopedia." 46 players have done this at least once. Then I went through all of those individual seasons and looked at their monthly & daily splits at Retrosheet & gamelogs at Baseball Reference. Here the only players I think have done this before:
Rickey Henderson-1985, 1990
Eric Davis-1986, 1987
Let me know if you think I missed anyone. Trout has a good chance to get 30+ HRs and 50+ SBs. Only two players have ever done that, Barry Bonds and Eric Davis, each once.