I think all the pleats and topstitching, plus the faux-fly look, are really an improvement on the elastic-waist pant. I did sew the knee pleats down from the inside because, in real life, they pouf out and certainly don't flatten themselves out again.
Khaki twill from Mill End Textiles.
Elastic from Cleaner's Supply.
Pattern: Kalle Outdoor Pants (Ottobre 4-2008-24).