Filco Minila Air • The Minila Air is the flagship of Filco's new compact Majestouch Minila keyboard family. It finally brings wireless bluetooth to mechanical keyboards of a main brand.
IBM industrial Space Saving Keyboard • The IBM Space Saving keyboard is an 84/85 key Model M keyboard. The iconic design of the standard version is only topped by the rare industrial version of the same board.
IBM "Kishsaver" • The IBM "Kishsaver" is a 62-key keyboard for the IBM 4704, named after it's rediscoverer, Kishy. It is the only true compact IBM Model F keyboard known, and got again in the spotlight by this huge find from tinnie.
Matias Mini Tactile Pro • The Matias Mini Tactile Pro is a "better keyboard for your Mac" and uses Matias Alps clicky keyswitches, making it an interesting alternative to compact MX keyboards.
PJE's OneHand - 20% keyboard • The OneHand chording keyboard is a custom keyboard project by PJE and a great example of how to build your own keyboard. It uses a custom PCB, Cherry MX switches and a Teensy controller.
And the Wingnut for Best space-saving/compact keyboard 2013, as voted for by the members of deskthority, goes to...