Wow, it's like a Dr Who episode where everyone is called Simon. My OB1.4 has a build area close to 200x200x200 depending on the extruder setup. Several other people have come up with better extruders and x-carriages now so I would probably use one of them if I were building another.
I have pretty much moved on from this printer now and am working on two other designs, one is a very simple printer made from 8-10mm acrylic sheet and will be a kit sold via a friend of mine in flat pack and the other is a one-off larger scale printer I am building with Misumi 2020 type extrusions and will have a build area of 300x300x300.
I am also associated with two different builders who are building very large scale 1mx1mx1m machines both running mach3 - it seems the way to go with bigger machines as there are a lot of CNC 4-axis boards out there that will run the larger stepper motors easily.