That's quite an assumption you're making on the interest rate tradeoff. No guarantee of 5% annual on RE, even if you're in an area controlled by bunch of NIMBY's.

The best model for that is to be a bank with the 3/6/3 model.

Borrow at 3%, lend at 6%, on the golf course by 3 PM.

Now doing something similar with stocks.... that's kind of Warren Buffett's model. He uses insurance companies like Berkshire and Aflac to create cash flows to buy stocks.

I guess you could use options to do something similar.