I was seeking a way to not make this a seperate network segment by adding a router or changing the MT to route.
Actually, it is better to have the customers location as a separate network segment. Using an inexpensive router at their location accomplishes this. You really don't want all their netbios traffic on your network, or for customers to be able to see each other.
I provide 1 static IP address to the customer location that is fed into a router. It NAT's that IP to their PC's and hands out IP's and DNS info by DHCP. They can add or change PC's as they wish, and it doesn't require any action on my part.
Proxim is one company that does MAC limitation. They use it on their MP.11 product line. The residential units only allow 8 MAC's and are not POE capable. The business units support 65535 MAC's and are POE capable. These units also do DHCP and NAT, so a separate router isn't needed (unless you are attaching more than 8 PC's to a residential unit).