It is not a velomobile, but it is certainly a very valid part of a transport portfolio.  In the how-stuff-works category is the following, short US produced video, showing the manufacture of an iconic British folding bike, the Brompton.

Now what we need is a video showing a velomobile being made.

But wait we do!  Below you can watch an Alleweder A4 build itself – apparently untouched by human hands.