Been a fan of headnockers and H2G2 (BBC version) for quite a while, so figured I'd have a go - and yes the does wobble thanks to the spring from a retractable biro ;D
I've just the parts to label and some simple instructions and it's there I reckon.
Oh, and since Marvin is by nature a mundane chap I decided the only way I could add a little interest was to throw in Eddie and a bucket from his car park days
Anyway - hope you all like it.
And I will probably provide a scaled down head for those of you who are desperate for Marvin with correct proportions.