A while back, we looked at a couple Scapeshift variants and a few decks that were trying to cheat Emrakul, the Aeons Torn into play. The key to finding a great mashup is finding pieces where the combos overlap, and Novaexplovise has found a new one.
Some Scapeshift decks are focused on casting its namesake card, although some use it as a backup plan in their Primeval Titan strategy. When you're playing with Primeval Titan, Summoning Trap is a good addition. Then again, Through the Breach isn't that bad with Primeval Titan either. At that point, playing Emrakul, the Aeons Torn looks pretty appealing.
Summoning Trap covers you against counterspells, even Remand, while Through the Breach allows you to beat the fair decks. On top of all that, you still have the good old Primeval Titan/Valakut, the Molten Pinnacle Core. Only having a singleton Scapeshift might seem kind of odd, but you don't even want to draw multiples, and the deck has a ton of other stuff going on already.
If you're looking for a different way to take your opponent by surprise in Modern, look no further.
[Editor's Note: When researched by Gerry, this list was published with a 13 card sideboard. As such, like you, I'm left wondering what the other two awesome cards are.]