Have you thought about laying the wire down at the juncture of the carpet and baseboard and running cable around the perimeter of the room? They make moulding strips that can then be applied to hide the wire. Pulling non-flat cable under carpet doesn't work very well--it tends to leave a ridge/bump across the carpet, which can be very noticeable if you're using 12/14g wire. Flat wire is always an option, but it can get expensive.