Apparently the Giezendanner brothers started a company making electric retracts at some point in the 1970's. There is a [link=http://www.giezendanner-technik.ch/shop/index.php]Giezendanner Technik website[/link] which offers the retracts for sale online from Switzerland. I haven't ever seen a set myself, I simply found the site while searching the Web for information on Bruno Giezendanner and the Marabu.

The nice big picture on the site's home page should find approval with a lot of people on this forum...

Best regards to all.