I just discovered that my favorite brand for dry beans and lentils offers a number of products in long-term storage buckets including beans, lentils, and a number of grains.  They even have Einkorn wheat, which is an old world wheat that is suitable for those with gluten sensitivity (it does have some gluten, so not suitable for full on Celiac Disease, but it's way better than modern wheat). 

https://palousebrand.com/search?q=bucket

If you click the bundle option at the top of the page, you can buy multiple buckets at discount, with the discount getting bigger with the more products you add to the bundle.