You want this stuff: http://www.amazon.com/Install-Bay-Split-Loom-Inch/dp/B005V9U... Of course they chew through that too, but it takes them just long enough that you can move the cable/distract them before they get to the cable itself.

Also, our rabbit tends to ignore cables that are flat along the ground. Only diagonal ones that cross her path ever seem to draw her attention.

Owning a rabbit isn't hard or dangerous to them, but yes - letting them have free reign of a room means completely bunny-proofing it. I've lost so many cords...

It's not as bad as you might think if you use e.g. pipe insulator to encase your cables.