mtg, mtg cards, magic the gathering, gaming, geeks
As mentioned Battle of Wits is useless in EDH as, at the most, with Battle of Wits on the table, you would only have 98 cards in your library and you need at least 200 to win with Battle of Wits . And 98 is best case scenario, you would have to get rid of all other permanents, including land, and get them all back into your library.
In official EDH rules, you can only have 10 sideboard cards. The first comment answered this question. You can't build a Battle of Wits EDH deck.
And even if you could have an unlimited number of cards in you sideboard, you'd have to play a wish more times than is practical, including the 18 eldrazi cards you could sideboard in with Spawnsire.
So no, you cannot build a Battle of Wits EDH deck.
@ jakerr101, the "official rules" have it as an optional rule. Most competitive EDH/commander tournaments will play the sideboard rule I assume such an awesome rouge deck will be for casual play.
"...These cards let you get cards from "outside the game," which has been ruled to include your card collection (in casual games), your sideboard (in tournament games)..."
So if anything, a casual playgroup would be obliged to let DrkNinja use cards he owns even out of the sideboard.