The firmware is a DiamondAge fork of repetier (http://www.repetier.com/) and Slic3r for making the files (http://manual.slic3r.org/)

RE Shipping: http://diamondage.co.nz/help/faq/#FAQ-7  They do ship worldwide but this is a separate quote per country.

The software and the hardware are both open source.

These are competitively priced for the NZ market and as you say they do have a larger bed than normal.   Unfortunately shipping will add extra cost when sending overseas.