Think Tank Retrospective is supurb - pick a number - 10,20,30.
My favorite is Domke 5xb - lightweight and durable
Tamrac has a couple of new messenger back so I would suppose Lowepro does also.
Billingham Hadley is georgous but pricey.
Naneu Pro Lima is rugged, cheap and comfortable.
"Pays your money, take your choice"