The closest we’ve ever seen to Sony Ericsson entering the personal computing market was its XPERIA X1 smart phone, a Windows Mobile phone with a full QWERTY keyboard that the company launched in 2008. But Netbooknews.com has word that the global cell phone manufacturer is working on a smartbook.

Smartbooks are ARM-powered devices that are slightly smaller than netbooks that offer longer battery life and mobile broadband connectivity all in a thin form factor. However, these devices aren’t as powerful as your typical netbook and don’t run full Windows.

Rumors have it that Sony Ericsson’s device could sport either Qualcomm’s Snapdragon chipset or NVIDIA’s Tegra processor, although there isn’t any news on specs at this time. The inclusion of either would likely allow give the smartbook enough power to output full HD video to a TV and enable light gaming, though the latter solution should have better graphics muscle.

Given that Sony’s Mike Abary was pretty down on smartbooks in a recent interview–arguing that if consumers see a clamshell design, they expect laptop-grade performance–we doubt Sony proper is working on such a device. But Sony Ericsson could very well be kicking the tires of the smartbook category.

We just wonder what OS Sony might be tinkering with under the hood. Android? Windows CE? The bigger question is: Would you buy a Sony Ericsson smartbook? And if so what would it need to have?