Smallest Scale Autonomous Republic

What is a republic or city state? Perhaps more apt is republicOS, an republic that is based on open source, collaborative development as its core operating principle, as carried out by integrated humans.

Using Open Source Microfactories and Open Source Material Production Facilities - what are the practical limits of what can be produced easily on any parcel of land?

Lumber, concrete, and steel are relatively easy to produce. See Steel Production. https://edge.alluremedia.com.au/uploads/businessinsider/2017/11/iron-ore-steel.jpg