From what it looks like in your post of the original advertisement, perhaps you didn't actually get any frame tubes. Maybe it came with plans to cut your own tubing to suit.
The major lugs are obviously adjustable for angles to suit the different frame geometry you'd need for different styles, bmx, bici cross, tandem etc.
I like the "antica" (penny farthing style) design, but my favourite would have to be the 'rekord' version, a design nod to Moser's lo-pro hour record bike, very cool!
Might be worth enquiring with a museum that has one, before attempting anything too drastic.