Vredestein tyres have two options for you,
http://www.vredestein.com/autobanden/Index.asp?TaalID=3
There's the Perfect Moiree at 26 x 1.75 and the B-EACH tire at 26 x 2.125.
The old IRC Metro is available at 26 x 1.5 as well.
EDIT: Actualy I remember that the IRC Metro's used to be available in a bigger size as well. Maybe its still around.
You've already posted a picture of the Continental option. 1.6" is pretty cushy.
Regards, Anthony