Unicomp owns the rights to the design of IBM Model M keyboard, and makes modern version of keyboard with the classic IBM buckling spring key switch mechanism.
[see IBM Model M keyboard]
Unicomp Keyboard Review
Here's a interview with Unicomp guy Mr Muyskens
[Old-School Keyboard Makes Comeback Of Sorts By Mr Muyskens. At http://www.npr.org/templates/story/story.php?storyId=100076874 ]
Here's History of IBM Model M, and Review of Unicomp keyboard.
The buckling spring is a old tech. There are few other key switch mechanisms with good tactile feedback.
See Keyboard Key Switch Mechanisms