Treven,
Lean runs arent the only source of high heat, extreme frictional pressures also cause heat build up, this is particularly true in our diesels at the wristpin and to a lesser extent the bigend brg, places that Andy has found to fail in some of his tests with no/low lube fuels. So to say the benefits of castor arent relevent outside of lean runs is a misconception.
Re the other uses of castor, it is widely used in go karts and other competion 2 strokes as well, its non use in automotive 4 st's is due to its natural ability to form larger molecules , which over a short time would cause the oil to become a solid,but research is being done to stabilise vegitable oils for use in automotive 3st motors due to the looming shortage of mineral oils.
Stewart