http://www.indiegogo.com/HBFS30
It's a 30mm button which uses Cherry MX switches for longer life, lower noise & higher customization (can fit Cherry MX Red, Black, Brown or Blue).



Decibel test (youTube)
He's about half-way to his funding goal of $8'000, and if he doesn't make it they probably won't be mass-produced.
So... pre-order them, is what I'm saying.
I'm not associated with him, I just really want to see these being made