Just a heads up on the mormon comment.... Every mormon congregation (called a ward) in the states has access to either a cannery or canning equipment and bulk grains, beans and foods. The way it works is you buy what you want and then help to can your and everyone elses orders. I've done a lot of work trying to find the best prices and the prices I can get there are better than anywhere else after you figure in the shipping. It takes a couple of hours of time, but well worth it in my book. Look in the phone book and I'm sure you can find a listing for Church of Jesus Christ of Latter Day Saints. Call and ask about it.
Also, for the rolled oats, or any other grain you can buy food grade 5 gallon buckets and put them in there with oxygen absorbers to remove the oxygen and keep the bugs out.
Another good place to look for bulk grain, flour, legumes, sugar and pasta is resturant supply stores. Here in washington there is a chain called Cash n Carry which caters to businesses but you can shop there as a private individual.
hope that helps.