Look to local quarries, some will sell larger than gravel size. They tend to use different terminology for the different sizes, but if you merely ask for 5 inch rock or 6 inch, or whatever size you need, they will be able to set it up so long as they offer that size. An alternative would be to call some excavating companies and see if they have access to creek rock. If they do, they will have a dump truck and something to load it with. You should also inquire about them placing the rock with a skid steer unless your pond slopes are too steep. Then you may have to do it by hand and bucket... Yuck, but that's how my rock got moved from a nearby creek. Rock farming is not the greatest of fun, but the results are nice.

Fish on!,
Noel