It's all well and good Research in Motion releasing teaser video after teaser video showing off the BlackBerry PlayBook, but sooner or later it is going to have to actually release the actual device.

And whilst we don't know when it will be hitting the shops exactly, we do now know that a second, 4G enabled, version will be hitting the US in the summer of 2011, after a tie-up with network Sprint was announced.

"RIM believes a significant portion of the tablet market will want a higher performing, multitasking, professional-grade tablet and that is why we chose to design the BlackBerry PlayBook for premium performance with a powerful dual-core processor and multitasking OS," said Mike Lazaridis, president and Co-CEO at Research In Motion.

"Together with Sprint, we are now building on that performance advantage with 4G and providing an unparalleled mobile experience for users."

"This tablet is a great example of Sprint?s strong partnership with RIM in continuing to bring customers powerful devices to enhance their mobility," said Steve Elfman, president of network operations and wholesale for Sprint.

"We are confident the BlackBerry 4G PlayBook from Sprint will be one of the most anticipated tablets in 2011."

4G for tablets looks like being big in 2011 with AT&T also announcing at CES that it will be releasing a number of slate devices with manufacturers this year, and the 4G Motorola Xoom also coming in Q2 2011.

Keep up to date with all the tablet news (and believe us there's a lot of it) from Vegas using our dedicated CES homepage.

CES 2011 Tablet-counter: The score so far...6