Hardware/accessory vendors?

I’m looking in particular for a shoulder strap for a product I’m creating, but can’t find a “general store” of sorts for this type of product. I’m looking for a strap and panel mount studs. The connection mechanism would be perfect if it was like the overalls I wore when I was a kid (read Osh Kosh). What I’m looking for are one-stop-shops for handles, straps, etc. so I don’t have to design EVERYTHING or search the entire web for an off-the-shelf-item.

Usually I can find a latch I need or something else, but there is never a single place that has all this type of hardware. Anyone got any sites?