I've started building the dome - ie the head part. I'm building an initial full-size model out of paper, on the grounds that it's cheaper. Much, much cheaper. So, an hour or so spent with scalpel and rotary cutter have meant I have the beginnings of a dome.
It's not going to be the final version, but it's worth doing - if I end up going to a local plastic cutter to get the sheet styrene cut, if I can give them a DXF or DWG it will be easier.
So I've used a bit of mathematics to build 1:1 scale, flattened PDF versions of parts.
So I've got the top section cut out (at least one, I'll double layer it), and the mostly vertical bit of the head. Next will be the neck, and the body skins...
And on their way - two 24 volt, 100 watt motors, with a mounting frame and wheel!