westfw:
I am starting to be a little worried about a TCP/IP chip that doesn't support IPv6.
I don't, because my experience with looking through access logs on embedded systems I've deployed has led me to divide 8-bit (and even many/most 16-bit) networked micros into 3 categories: "firewalled", "screwed", and "not screwed yet".
There are so many zombie PCs out there that you just can't put simple systems on the net without something to protect them from being swamped by incessant probing. The router(-ish) device that connects them to the Wild Wild Web will eventually be one that translates between IPv6 and the legacy devices on the LAN running IPv4.