Was looking on the site for some ideas for a strap for my new Seiko 6138b and noticed that Ming's been looking for a rubber strap for his dreadnought.
Howard Marx is selling a 22 mm strap with integrated deployant.
http://www.westcoastime.com/rubberbands.html
Ming is this what you're looking for?
Thanks expat...but no, having got my kaufmann I've given up in my quest for fitted rubber on the dreadnought :)
Ming