The only way to get the i7 is to go for the 1499 model and upgrade the i5 to the i7. The 1499 model comes with the 256GB ssd by default so you don't have to worry about that. If you want the i7 with a lower capacity ssd than this won't be possible as the 1499 model is the only one that is upgradable to the i7 but you can't downgrade the ssd from say 256 to 128GB.
Btw, I'm only speaking about the 13" model, not about all the Air models (aka both 11" and 13")!