How to maximize after-tax cash?

[James Baxter]

Hi all, I own a few properties in CA, but I'd like to buy a home to actually live in myself in the next few years.  I'm currently renting in a pricier part of SoCal and would love to buy a home there, but houses start at $1.6M.  The down payment alone is daunting, but the ~$8000/month mortgage for 30 years is what really spooks me.  Making that work is a tough prospect, but I really want to see if I can get resourceful and make it happen.  

The idea: buy a property that can yield a lot of cash and knock out a bunch of the monthly payments.  My hope is that I can find a place for around $1M that will yield 20% after tax, something like $3,300/month.  That will take the $8k/month down to $4,700/month.  I should be able to refi one of my other properties for a decent chunk of change before too long, so within a few years I can have the down payment.  And voila!  A down payment with a nice little money printer to help with the mortgage payments.    

First, is this a good idea, or is this actually hare-brained?  Second, where is the highest yield on after-tax cash?  I'm willing to look anywhere in the US.  Lastly, if this a sound plan, is my 20% goal realistic? 

I'm currently in south Chicago looking at properties, but haven't found anything that fits the bill.  

Thanks for any advice you have!