I recently found a nifty solution for the crippling problem of cable management. It might not be suitable for super computers but it does work for my desk.
It was built by screwing Ikea Antonius coat hangers to the underside of the desk using long enough wood screws. To give it a bit of stability, I used a hollow tube (like piping cut to length) for the hangers to sit on.
Here are a few pictures:
Simple and inexpensive…
Due to popular demand, here is a diagram I cooked up in paint that better explains the mounting mechanism. I have no particular suggestion for the length of the pipe except that it should be long enough for the hanger to clear the table (so you can slide the cables in). If my memory is correct, mine are 8cm. As for the screw, just make sure it is long enough so it can drive a good 2cm in the table.
Sorry for the lack of information, next time, I will be more thorough in my description and will take more pictures.