Hi,
I think it will depend where your VLAN sub-interface terminates. If you are using a router with a 100mb/1000mb interface with multiple sub-interfaces connected to a switch with dot1q, you can configure these into vrf's like any serial interface. If you are using a 6500 with a SUP720B and upwards, you can configure the vrfs directly on the SUP.
eg:
int f0/0.1
encap dot1q 1
ip vrf forwarding VPNA
ip 192.168.1.1 255.255.255.0
int f0/0.2
encap dot1q 2
ip vrf forwarding VPNA
ip 192.168.2.2 255.255.255.0
