Linear Cherry MX Switches allow you to push the switch half way down and it actuates. The same as Tactile or Clicky Cherry MX switches.
As for a Red LED Backlit board; I would suggest waiting a bit for Cooler Master's offering to come out.
It should be more affordable than the Deck; feature the same Cherry MX-Black switches, but offer more features.
Build quality and details have yet to be announced but at Computex, they said it would come out this year.
Tactile - There's a "bump" during the travel of the key to let you know that you've pressed the key. (Like most keyboards)
Linear - No bump in the travel of the key, the key just gets progressively stiffer to press until it bottoms out.
You can have linear switches that do not need to be bottomed out, and tactile switches that do need to be bottomed out (e.g. rubber domes)
+ Rep to ya'.