I would also like to point out that your customers will probably appreciate it if the Wixels have unique serial numbers, and I have not actually heard of anyone having trouble because of ridiculously high COM port numbers. I would be interested to know if there is actually a problem with really high COM port numbers, so I would suggest that either Tim or PeterPan just let it happen and share the results with us.
Another alternative is get a Linux machine for programming the Wixels.
PeterPan: What makes you say that “Polulu recommends not using the wixel directly in a final product”?
–David