I've cloned a ton of pokemon to transfer to Diamond.
All I've cloned and transferred:
Metagross, Tyranitar, Salamence, Dragonite, Shedinja, Blissey, Latios, Heracross, Aerodactyl, Marowack, Machamp, Nidoking, Dugtrio, Registeel, Skarmory, Steelix, Starmie, Lapras, Regice, Togetic (Evolved into Togekiss), Shuckle, and Cradily.
I know, too much time on my hands.
Oh, yeah, you can clone six pokemon at a time, that is also how I got so many cloned (Cost me my Metagross
)