Ive played with the idea on my own PC running two test boards and it works with some minor complications which would need to be recoded.
However running multiple boards on the same server, I'm not sure it could handle it. My guess is you get to many and you would crash it. So to run multipe boards of 50 you would need multiple servers. Im not exactly sure how ezboards.com and gamers.com run all those boards under the same domain. My guess is they have great networking guys in the background able to map that out or there boards are coded different.
Im not a network expert so Im not sure how that would work.