I'm going over the Cherry MX spec sheet (http://www.cherrycorp.com/english/switches/key/mx.htm), and I notice one of the mounting options is "metal frame." Are there any keyboards that actually use those? I imagine it would add a ton of weight, and flex less when you're banging your head against it.
It's more commonly referred to as "plate mounting" meaning there is a metal plate surrounding the switches above the printed circuit board. Filco, Leopold, Ducky, Deck and Das keyboards all have plate mounted Cherry MX switches.