Heh, anyone that worked at Apple or SGI in the 90's could probably cover their entire request :-) Friends there used to joke that first thing a project did was design the t-shirt and print them, if it was a "cool" t-shirt, only then could the engineering begin :-)
My local goodwill has received hundreds of swag shirts from me over the years. I like to think the local poor in Miami are benefiting from the dot com boom at least indirectly.
Given they're holding conferences etc. I imagine companies would be willing to make a decent donation to the IA if they used their branded cushions? At the very least I'm sure people like Mozilla and the Wikimedia Foundation would send t-shirts.
We did a few clothing drive parties and had folks send us old startup swag to give to goodwill (and a Jamaican orphanage). Can definitely contribute to this also!