My mother let us go through her huge rhubarb plants, with stalks more than 2 feet in length. We quickly picked enough that we had more than 25 cups of diced rhubarb. I used 16 cups of it in a rhubarb BBQ recipe. I did make some of my own substitutions. Instead of just brown sugar, we used up some pure cane sugar and some dark brown sugar that came in hard sticks. I had them sitting around from when we were trying out different sugars from the Asian food store, but it was just not very convenient to have hard bricks of sugar, so I used them up in this recipe. Instead of vinegar, I used apple cider vinegar. Instead of raisins, I used a combination of raisins, craisins, and dried cherries.
We also took an immersion blender to it when it was cooking. A doubled recipe made 5 quarts and 5 pints.