A River Crossing puzzle puts limits on the number of items that may cross a boundary, with limits on what may be left together. The "Fox, goose and bag of beans" is one of the earliest examples. Of course, by increasing the capacity of the boat, or the number/type of barriers, infinity is the upper limit. For this question, I am asking with the classical configuration of one barrier, with a limit of one transport per move. You can increase the number of items and their ability to coexist.
What is the largest number of items in a solvable river crossing puzzle that has been documented? What is the maximum that could be created?