Is there a business that sells concrete? This is an item that is used mostly by contractors for large concrete slaps that need reinforced. Look for the concrete trucks and see if they have a retail department that sells supplies.
I do not use fiber mesh n my hypertufa unless it is large piece. Keep it moist for several days and it will cure properly and will very strong.

Here is a link that might be useful: my blog

As Mike said you really don't need fiber mesh. It's not necessary for the small pieces that are made by most people. BUT if you're building a bridge then go to a masonry supply house.
Mike, Just saw your blog. Beautiful pics and texts. I may have accidently posted a comment twice so just ignore one. I'm headed back to read more.