Want to build an isomorphic keyboard

[veclock]

Hello! I'm new to this forum, please move the thread if it's placed in the wrong category.

I'm planning to build an isomorphic keyboard like the Axis64,
and I want the buttons to be velocity sensitive.

I'm a total noob in regards to electronics and I don't know where to start really.

The buttons should be around 2-3 cm wide. Closest thing I've found is round arcade buttons:
http://www.arcadeworlduk.com/products/Translucent-Illuminated-Arcade-Button.html

But they are not velocity sensitive and they have a plastic frame around them, making it impossible to squeeze the grid of buttons tightly together. The frame will create spacing between the buttons... So I need buttons like these: http://i2.wp.com/www.synthtopia.com/wp-content/uploads/2007/01/c-thru-music-hex-keyboard.jpg?w=640 (it's an Axis64)

Thanks in advance