He sends me back a text, all huffy, about how it's not real smart to deny a qualified renter by electronic communication, like he's making a threat.I told him, unless he's a member of a protected class, i can tell him to take a flying %$#@.    

Make sure you are protected with a recorded mortgage, that the property the mortgage is recorded on is worth more than you loaned, and that the property is properly insured.

The 2% rule seems to be intended to protect against long term expenses (carpet, painting, roof, etc) but if the cost of the home is so much larger than the upkeep expenses it should instead get back to a cost per square foot to maintain-- Example 2000sq ft * $3/yr = $6k/yr for maintenance seems much more reasonable then needing to go achieve the $18k/month route to suggest cashflow.

The most important thing to note from this post is the fact that some the information you are using to make your decision is protected under fair housing laws.

As a property manager, to protect my client, we execute a lease and take the deposit before the house is removed from the market.

The 1st thing I did was get a lawyer to create a lease that incorporated all of my policies (which he modified so they would be legal and enforceable) and set up a LLC and an umbrella policy to protect our assets.

This is a strategy a lot of people use as they get older, when rate of return is not quite as important anymore as protection of principal.

Form your corporation to help protect you personally.  

@Antoine Baisy, consider also Protect America which have some of the lowest monthly costs.   

I also agree about making this a legal entity for protection for the both of you/