Regular tablets are good for media consumption, but don't fare so well when it comes to doing digital drawing and photo-editing. Similarly, Apple notebooks lack the touch-capabilities for you to perform some delicate photo-editing. That's where Modbook comes in — the company is known for converting Apple notebooks into pen tablets by combining Wacom digitizers with Apple notebooks. Its latest project, the Modbook Pro X, will convert your Retina MacBook Pro into a pen tablet. The Modbook Pro X will have the Retina MacBook Pro's original hardware, but will also support pen input with 2,048 pressure levels. There's also tilt and rotate functionality. Since such a large-scale mod will void your warranty, Modbook will provide a one-year warranty, though you're able to purchase a three-year warranty from Modbook if you would like extended coverage. Head on to Modbook's Kickstarter page if you're interested.
Source: Modbook Pro X (Kickstarter)