Yep, but KVM's are ass

I would rather have one powerful machine that can do the work of 2 boxes, in one smaller space, making less noise, and having to invest in only one high end disk IO setup. KVM's also arent cheap when you need one to switch USB devices, DVI links to monitors, and 5.1 sound. To be able to use all the features of 2 machines is expensive on its own.