Hello! Sinnoh is in progress, so we're gonna have a lot of new Pokemon to train. Maybe it's good time to introduce EV Power items? They work similar to Macho Brace - half speed and give additional EV points. But instead of doubling points each item gives 4 more points for specific stat. For example: If you beat Diglett with Power Anklet, you will get 1 + 4 SPD points, so 5 points is the lowest amount of EV you can get. There are total of 6 items, so you could add them as Boss rewards for bosses which are the easiest or those which have the worst rewards. I suggest 2 Power items per region:
Kanto:
Power Belt (DEF) - Brock
Power Band (SPDEF) - Pumpkin King
Johto:
Power Lens (SPATK) - Sage
Power Bracer (ATK) - Bruno
Hoenn:
Power Anklet (SPD) - Lt. Surge
Power Weight (HP) - Old Lady Janice
Hope you will like this idea :Grin:
For more details you can check this LINK.