This is what I'm saying....not suggesting one mix assets, I'm saying that someone could and the IRS knows that which is why they are extremely strict on these things....it's a super red flag and almost certain audit which will require the owner to basically prove all of the above things didn't occur.

At the very least it would require a very good level of accounting etc.

That's all I'm saying.  I used to do a ton of work with IRAs....I've never seen this work ever, other than for the very wealthy.   I've seen lots of people try but never seen anyone do it right for a decent period of time and not have major trouble / headache.

Small businesses, closely held businesses, non public stock, real estate / income property, metals etc. there is huge demand for this from many many people.   

I guess the question to ask is if you've ever seen anyone do this successfully over a few years....you can also ask accountants and lawyers.