Sounds cool, if even true, but need more details ? I doubt this will be like a "Nexus" device with updates direct from Google ?
I could see it being shipped with Android 4.3, and being stuck on 4.3 for awhile,waiting for Samsung to push the newer OS update months later. And I agree, would be sold in very limited quantities, near impossible to find. So maybe T-Mobile gets it, ok, T-Mo blows, and I would still think would be scarce and hard to get at T-Mobile stores.
And the price for such a phone ? If it's in the crazy $650 range, no way then. With the current and still fresh Nexus 4 selling for just $349, no way is this special edition S4 worth 75% more, just for LTE, and expandable storage ? LOL, that's not worthy of a 75% price increase. The Nexus 4 is no slouch, hardware wise compared to the S4, is not that much different, sure the S4 is a better device, but not night and day radically better, if anything this S4 Google Edition would be like a Nexus 4.5.
At this point, I'd just wait for the Nexus-Five, will be cheaper, and have better spec's than the S4, and run the latest Android OS.