The deals I underwrite have been cash flowing right up until I put debt service on them, even with taking a break even amount in a refi. 

My buy box is a home 5 years or newer, A or B-rated schools in the 200K-400K range that will appreciate over time with someone paying down my debt.

So now instead of feeding the hungry stock market you can feed the hungry rental.I have watched people keep big debt on their home and then have the stock market crash.

I do have them sync their bank accounts and credit cards to eliminate human error in entering items, and ask them to avoid putting personal expenses on those accounts.

If this is done, then 75% of the gross rent for your current primary can be used to offset the mortgage debt of that property to 0.

If valuation came in at 50% of investor debt, then it would seem that share valuation would be just that, 50%.

With over an estimated $300 billion of extremely delinquent debt yet to be liquidated to the secondary market, there is a a lot of opportunity to reposition these loans, keep folks in their homes and make a very nice profit for all involved. 

Ownership is different than who's in debt. 

While 20% down improves cash flow by eliminating PMI, it delays entry into the market, potentially missing appreciation.

Maybe you could find someone who wants to be debt free and have a large place.