Fons and Porter has a line of the mechanical pencils like Sewline. I am totally in love with them! Creates a fine line, remains where you put it for a remarkably long time but washes out easily!
Here's a tip: I just ordered the refills (they are 9 mm), bought a set of three mechanical pencils at Wal-Mart for less than $5 and use the chalk refills in the cheapo pencils rather than paying $15 for one of the name brand pencils.