YongJun MoYu 13 Layer, made in China, 2015.
(plastic, 5+1/4", over 1000 pieces, weighs 5+1/3 pounds)
The patent for the Rubik 6x6x6 and Rubik 7x7x7 cubes presented designs for up to 11x11x11 cubes. Subsequently 8x8x8 through the Rubik 11x11x11 cube were mass produced. However, it was generally understood that dimension 11 was as far as that patent design could be taken; this cube goes further by modifying that design with extra tabs on the ends of some pieces. Tony Fisher does an impressive job in a video showing a complete disassembly of the cube, and a second video showing a reassembly; he identifies 38 piece classes.
Even larger Rubik's cubes were custom made before this one. In February 2011 Oskar Van Deventer presented a Rubik 17x17x17 cube called "Over The Top". It was fabricated using Shapeways 3D printing technology, and made available for purchase on that web page.
Further Reading
Tony Fisher Disassemble,, from:
https://www.youtube.com/watch?v=JlbsR--UVf8Tony Fisher Reassemble,, from:
https://www.youtube.com/watch?v=xP8AdF8Tl-wDeventer presentation February 2011, from:
http://twistypuzzles.com/articles/building-17x17x17/building-17x17x17.pdfShapeways Page, from:
http://www.shapeways.comRubik 17x17x17 Video, from:
http://www.youtube.com/watch?v=ihWyzvOM9pkRubik 17x17x17 Disassembly Video, from:
http://www.youtube.com/user/OskarPuzzle?blend=2&ob=1#p/u/2/CBY7JRh2YOoChris Hardwick's Page On Big Cube Speed Cubing, from:
http://www.speedcubing.com/chris/bigcubes-info.html