Most members are not that active. And for 1 shirt 70 signatures is a hell of a lot. I think that we have enough people to keep things interesting for a while. And it can get updated in the process- its not like its going to get back to you in 2-5 business days. :P
It is going to take a shitload of time just to wait for snail mail to get the shirt around, never mind the time that we get to keep it. It'll probably be gone for well over a year, and there'll be very little room left on it for anyone near the end. If you figure an average of two weeks per person (including time it takes to ship) you're looking at more then 2 and a half years right there.