3G-enabled Nexus 7 back in stock, but no such luck for Nexus 4

The 3G-enabled version of Google's Nexus 7 tablet is back in stock on the company's Play Store in the UK, ahead of the Christmas buying rush.
The mobile broadband-ready device was launched earlier this month, alongside the Nexus 4 smartphone and Nexus 10 tablet. Like those new devices — a Wi-Fi-only version of the Nexus 7 had already been on sale — the new version sold out almost instantly.
On Monday morning, the 3G-enabled Nexus 7 is showing on the Play Store as being back in stock. The Nexus 10 is halfway there ("Ships in 2 weeks"), but the Nexus 4 is still completely unavailable, making it unlikely that it will become available again at Google's relatively low pricing before the end-of-year buying season.
Some operators such as O2 are selling or planning to sell the Nexus 4, but at a far higher price than Google would be charging if the device were not sold out through its site. Three, for example, will charge £400 for the £239 device.
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Google's pricing for this year's Nexus devices has been unprecedentedly aggressive. With the Wi-Fi-only Nexus 7, this acted as a stimulus to other tablet makers to push down their prices too.
With mobile phones, though, operators are used to locking customers into two-year contracts — as the hook there is the operator subsidising the handset, this is more difficult to do with a device that is cheap enough for people to buy SIM-free.
That makes the Google Play Nexus 4 pricing particularly disruptive, and will have likely brought the company into conflict with those carriers.