Toby Leary Fine Woodworking Inc. These are a blind corner base system from Kessebohmer. These are usually provided by industry professionals because they need to get the right size for you. If you have a custom kitchen or a good quality kitchen from a showroom, they should be able to get you one. If you are retro fitting an existing kitchen cabinet I could help you. Feel free to email me at toby@tobyleary.com. Thanks!
http://www.xn--kessebhmer-jcb.com/en/company-divisions/kitchen-furnishings-equipment/corner-cabinets/lemans/
http://www.xn--kessebhmer-jcb.com/en/company-divisions/kitchen-furnishings-equipment/corner-cabinets/lemans/