I have a not-so-small number of computers (say, 5) which I want to access with a single keyboard, USB and monitor. I can get an 8-port KVM switch, which is a pretty expensive piece of hardware; however, in theory, I should be able to cascade KVM switches: Have one 4-port KVM switch between 2 other KVMs (a 2-port and a 4-port).

Is this doable (with typical off-the-shelf switches and cables)? Has anyone had experience doing this?

Note: I'm interested in USB-only for the keyboard and mouse, and either VGA or DVI for the display. Audio and PS/2 connections are irrelevant for me..