AT&T blocking iPhone SlingPlayer 3G in advance of own rival service?

We loved SlingPlayer Mobile for iPhone but hated AT&T's 3G network-access limitations when we reviewed the app earlier this week.  At the time, we suggested that AT&T were discretely uncertain that their 3G network could hold up to thousands of iPhone users streaming video from their Slingboxes; now, according to a Gizmodo tipster, there's another reason on the table.  AT&T is said to be working on its own, rival system, called i-Verse.

i-Verse is apparently another string to AT&T's U-Verse home TV and DVR system, which would add the ability to remotely view content – over their 3G network – on your iPhone from a U-Verse setup.  You'd also be able to load recorded shows from your U-Verse DVR onto your iPhone over your home network.

According to the tipster, AT&T made a number of closed-door demonstrations of i-Verse last year, and based on positive feedback went on to pump time and money into full-scale development.  If this all pans out to be true, it's a pretty crappy move by the carrier, intentionally crippling a rival application (and potential hardware investment by their subscribers) to give their own system an edge.