Once again, I'm amazed at your resources, Fernando. That description does seem to leave alittle room for a rounded bar. Now that I know the term 'palanqueta', I will try to do some research.
Here's a real one (sorry, Moderators, couldn't download pics from this closed auction). Square barred, but at least it has the full round balls-
http://www.ebay.com/itm/Bar-Shot-Can...-/300601305058