Ooooo canned speckled butter beans and purple hull peas! The pot liquor would be right there in the jar! Interesting, the same would be true of Red Beans - for Red Beans and rice. I guess you would cook up a big ole pot of Red Beans with all the ingredients - sausage etc. and just pressure can it?
I don't think you would fully cook the beans or peas before you pressure can them because of the length of time that they are going to cook in the pressure canner. When I canned the chicken, the instructions were to cook it between half and two-thirds of the way done and then pack. Seems to me like it was in the pressure canner for 1-1/2 hours, plus the time it took for the thing to cool down enough to open. Obviously, it would be fully cooked after all of that.
The other issue that comes to mind that you might have to watch if you can red beans with sausage, is the fat from the sausage. It is my understanding that you can't can very much fat because it tends to cause spoilage faster than other ingredients. If you were to skim as much as possible off before you packed the jars, you'd be in good shape.