What's the biggest reuseable filter with smallest pore size?
They can't be using these teeny filters, because customers can't wait
that long.

Specialty coffee shops that offer 'pour-over' (drip) coffee definitely make coffee to order using small filters like the one you show (although in my area, they usually use paper filters). Customers are fine waiting the 2-4 minutes this takes.
For larger quantities, what a coffee shop might call 'batch brewing', larger filters such as these are commonly used:

These come in sizes ranging up to 12 cups, but might be tricky to find. Alternatively, you could experiment using one or more layers of cheesecloth, which is perhaps more easily available and scalable, although it might not filter as well as you'd like.
As a final note, I think your demand for pore sizes &lt;10 micrometers might be a little too stringent. The filter you link to lists a .2mm mesh (i.e., 200 micrometers). I found this page with an analysis of the pore sizes in various coffee filtering products, if you're interested.