In the Netherlands there is a lbs that fits an adjustable stem
http://www.flickr.com/photos/plooifi...7603532527877/

More info, sorry it's in Dutch put the pictures tell the story too.
Go to http://www.bikeshop.nl/
then chose specials
then chose Vouwfietsen met Brompton en Brompton opties in het bijzonder
then chose Brompton Bikeshop opties
then chose Telescopische stuurpen