We first saw the prototype Panasonic 4K 20-inch tablet at CES 2013 in Las Vegas. But it won' remain a prototype for much longer. Yup, this mega-size, ultra HD tablet is heading to the shelves later in the year.Aimed at the pro market, the giganta-tab - which doesn't have an official name or price point as yet - packs in a 3840 x 2560 pixel resolution across its 20-inch LED-backlit surface. But it doesn't add on the pounds. Weighing in at around 2.2kgs, it feels really light considering its sheer scale.Tucked\u00a0in to the trim body is an Intel Core i5 1.8Ghz processor with Nvidia GeForce graphics and 16GB of RAM and a 128GB SSD for storage. We had a play with the Windows 8 touchscreen and all that power sure does deliver the heat - and we mean literally; the rear of the tablet felt very warm to the touch when rested on the one hand.The touchscreen felt generally responsive and we even had a play with an optional stylus that responded much like a normal pen. Writing, scribbling - it was easy to add notes over architectural drawings.Visually, too, the 4K tablet with its relatively slight bezel is all about the visuals. Flicking through a gallery of Lumix camera images the resolution and bright panel really shows its worth.How much, exactly, that will be worth we're yet to hear. Don't expect this tablet to be a budget buy by any means, but we're impressed with what we've seen.