There are sparse rumors of a fall release of possibly a 7" model, but I wouldn't hold hold my breath for one, nor a fall release of the regular iPad either.
Highly unlikely. They might start shipping models in the fall preloaded with the next version of iOS the same way that they had iPad 2 models (which originally came preloaded with iOS 4.x) with iOS 5. But that'd be it.
The move to a Retina screen was far more than just an upgrade. The possible introduction of an IGZO screen to reduce power use and make the design thinner is unlikely until the next annual refresh. There doesn't seem to be anything else on the horizon that would force an early new model.
It's a fact that the Fall iPad (dubbed "The Newest iPad") is going to breathe fire and print money. It also has the ability to become an iBed and an iCBM. Rock on Apple.
Remember that Apple "updated" the iPhone 3 twice before introducing a "brand new" model, and each update (3g, 3gs) iirc came about a year after the last, not to mention that it has done the same thing once so far with iPhone 4. Updates seem to "count" as new models as far as Apple's concerned.