I was watching this company the corpora a lng time all ready as they announced to release an open source robot platform, quite capable in all sorts of things, using the relatively new ROS robot operating system at that time back in 2010.
The main ROS target the PR2 robot is still a 500.000 USD machine and far from private reach.

Then a few years of development later in november 2012 the corpora finally finished their assembling and launched preorders for their QBO platform, and in addition published the sources dor hard and software on github.

QBO announcement on ROS website

So I started sourcing all the required parts, and at that time still thought of 3D printing or vacuum forming the needed chassis parts by myself.
It turned out it would be still to expensive so I further drilled down the costs for some parts. Cheaper but bigger sonar, waiting for used parts on eBay and so on.