Thanks for the replies ! I have made hall effect sensors for my CNC router, I think I used SS441's and they work great and reliable. However, I don't know what kind of range I can get from them. I used weak magnets for the router, I'll try some strong magnets and see how they do.

Unless the SparkFun RFID units can be modded to increase range, I don't think that will work, I think I need around 2 feet of range or at least 1 foot. I found THIS but the range is only around 4".

Thanks again, please let me know of any other ideas/suggestions.