I ordered my tent kit from http://www.questoutfitters.com/
They also carry a large assortment of the hardware you are looking for. They also have several different webbing options. They have a soft and firm gossgrain, as well as a couple different types of nylon webbing. I highly recomend them.
Depending on the width of the webbing on his straps, they also have a special piece for attaching sternum straps to packs that you may want to look at. I would also look at their whistle buckle. It has a built in whistle that is louder than any whistle I've ever heard.