A very close match for the material was found a few months ago by one of the moderators. However, the material had to be bought in bulk (at least $500 worth), and was only produced twice a year. So alot of TDHers were able to send in enough fundage to cover the cost and get the "TDH-approved" fabric at that time.
As for Jo-Ann's, you might be able to find something similar. I've used the inside (wrong-side) fabric of a light-grey satin, called Casa Collection something-or-other. It works well, but it may be a color shade or two off.
I believe the mods will try another fabric run in the near future. Keep checking the board!
There are at least several different shades of gray satin commonly available.
I just found some really good polyester stuff that I think is perfect. It's washable, it's fairly tough, it has a very slight sheen, and it's a really pale gray. I'm using it to make hoods now, but I'll probably save enough for at least one vest. I found it at JoAnn's, but the trouble is that it's one of those things where they order a big box of "assorted bulk" fabric. Nobody knows what this stuff is, and I've never seen it before.