Tripod straps are tough to find on messenger bags, which is why the LowePro ProTactic SH 200 AW is worth a look. Two sturdy straps secure a tripod to the bottom of the bag and could even be adapted to strap on a rolled up jacket. Besides just the tripod straps though, the strap system on the sides allows for using add-on pouches to expand the bag's capacity to fit your shooting style. The bag also feels more military grade than many of the shoulder bags that are designed largely for style. Constructed with an all-weather ballistic nylon, the bag will keep gear protected from the elements. The capacity is pretty good for a shoulder bag as well--accommodating a DSLR with a 70-200mm lens attached along with 2-3 extra lenses and a flash. The 13" laptop sleeve is also plenty roomy. Carrying all that gear is pretty comfortable with the well-padded, adjustable shoulder strap.
While the interior divided section offers quite a bit of space, the accessory pockets are a bit small for this type of bag. The trade off-for all that protection is also a bit heavier bag, and fully loaded with a tripod, the bag will be pretty heavy. Overall, the LowePro ProTactic shoulder bag offers add-ons and protection that is tougher to find in a shoulder bag. If you're looking for tripod straps but don't want a backpack, this is one to seriously consider.