You don't have the ability to trade futures options in OO today. You can sort of simulate ES options with SPX options, but the margin requirements are radically different between the two. It would be nice to have the ability to say "This trade requires $X margin." Today, I can only say "Trade X contracts of this and ignore the margin requirements." An alternative would be to say "Trade X contracts per $Y of account equity." This second one is already a suggested feature and should be implemented. It's not quite the same thing but could be used for this.