As long term forum users will possibly appreciate, I love making my own ourdoor gear, and have done so since my student days in MDs in the 80s
In the early days, I got my raw materials from MDs. I recall that there was also a place advertised in the back of "Wild" magazine which sold some material from Ballarat direction.
10yrs ago, I had to search reasonably hard on the net to find stuff. The last few years, we have had more options, but all off- shore. The primary ones I found were Owfinc, and Thru-hiker, but searching hard, I found other off-shore sites for some specific fabrics as needed.
More recently SimonM has offered us some fantastic DYI raw materials over this forum. I've recently bought some cuben, and some down from Simon, and I will probably also buy some Argon fabric from him (0.70oz fabric for down stuff....dependent on whether i already own some appropriate fabric). Simon sent me some samples of this ... it looks great.
He has some great stuff available, at very reasonable price, and I'm surprised at how much he has committed himself in this pursuit.
Disclaimer: I have no association with him in any way, shape or form. I just love the fact that someone will go "out there", and try to provide stuff like this in Oz at competitive prices.
Andrew A