Let me get this right... You want to extend the length of the IR sensor. Cat 5 will work fine for that. Are you using IRman? If you are there should be 3 wires going to the sensor (small black rectangle), just unsolder them and add the length of Cat 5 that you want. I was able to extend mine about 7 feet without any problems using a telephone cord. Personally I ditched the casing because like you I thought it was too bulky.