I have been reading through old threads and found this post, which mentions several experimental mashbills, from Bobby Cox:

Re: Corner Creek Bourbon
Sat Oct 19 2002 01:51 PM
L&G have some four grain whiskies that will be coming on soon and BT has some that will have rice or oats in place of the wheat or rye. Things will become more interesting as we go along on this great little adventure!
Does anyone know of any new developments in these experiments?

In homebrewed beer, oats will thicken the body and rice will contribute to a cleaner, dryer body. It would be interesting to see if those elements would carry through the distiller's beer into the finished spirits.