Okie. Been busy importing all sorts of Pokés from SoulSilver lately to finish the Kanto list (except for Articuno, Moltres, and Zapdos, which I can get after acquiring all 16 badges unless I find an Event one available somehow). Going to be forced to get my other game (W2) going so I can do the trade evolutions (also have to import Growlithe from there, found at Virbank Complex).
I have completely forgotten what we were trading, so I'll go back and review the conversation (likely 2morrow as I type) and leave another VM.
The advantage, if you have any two of B/W and B2/W2, is that you have one Keldeo to train in each game. There are advantages to that since they're outsiders (even to the original recipient) and thus won't obey you beyond a certain level if you don't have the badges. :D
Just need your FC and I can be online soon after, if you want to trade tonite. I'll have the PP Max that comes with the Event attached to it (unless you want something else).
I also have Keldeo, and mentioned it a month and a half ago. Was able to clone on an older model and now tradable. The Event Arceus sounds like an option; I am getting wild versions of Ho-oh and Lugia eventually, and have events of Darkrai, Victini, Mew, and Celebi.