Here's something interesting: GAME is offering up a trio of EA mobile games as pre-order bonuses for boxed copies of Dead Space 3, Sim City, and Army Of Two: The Devil's Cartel. Specifically, the UK retailer is dangling copies of FIFA 13 [$6.99], Need for Speed Most Wanted [$4.99], and Mass Effect: Infiltrator [$4.99] to anyone willing to throw down some money on these games before they come out.
The GAME "bonus" page for Dead Space 3 pre-orders notes that this exchange is an exclusive to the retailer. No other retailers in any other regions we've checked out are offering anything like this, as you'd expect since this is "exclusive" and all.
It doesn't seem crazy to assume that this will become a thing. iPhone games are probably way easier to distribute than DLC cards, inserts, or physical items. Plus, they're a lot more fun to own. And way more disposable.