Try the Ronhill Trail Cargo Shorts - back zipped pocket, plus 4 mesh stretch pockets, and with 2 loops designed to hold gels.
Shorts are silky smooth, fast drying and have bamboo anti-stink inners.
I got my first pair from Wiggle for £27, but next two from Rat Race - http://www.ratrace.com/279/products/ronhill-trail-cargo-short.aspx - down to £17 using code RAT101.
Edited: 21/09/2011 at 20:15