I came across a software-design approach similar to Five Sketches™. It’s called Design Studio, and was developed in the USA. I was intrigued to learn about Design Studio. When separate teams develop a similar response to the same challenge, it validates both solutions. In this case, the challenge is to support software developers as they design the mental models, interaction, and GUI for their products.
Design Studio was presented at a 2007 conference, and you can watch it on video: but the BrightCove video is no longer available to watch.
If you have information about Design Studio, please comment, below. Found it! Jeff White and Jim Ungar presented their Design Studio method at the IxDA 2008 conference, in a presentation titled User Interface Design in an Agile Environment: Enter the Design Studio.