For example if you want to roll over 401k pre tax funds, you would obviously want to open a traditional IRA.

Bill Gulley 's example is exactly what I'm talking about, localities seem to differ on what the "tradition" or local laws, or interpretations thereof are about occupancy, which I find silly. 

I glanced over the spreadsheet you made and i think you missed a few key factors. 1) Securities can also be leveraged, granted not anywhere near as high of ratio as RE but it can still be leveraged. 2) Liquidity, you can constantly re balance and fine tune your traditional securities portfolio daily, which allows you increased ability to avoid risk or capitalize on opportunity, essentially minimizing opportunity risk.

I work with some investors who stick to fourplex's or less because they can stick with traditional fixed rate loans.

I will likely have reached the max number of rentals I can purchase with traditional Fannie Mae backed loans in the next year or so and am trying to learn more about other financing options.Thanks!

I've never done it but have heard it can be less costly than a traditional loan.    

For rentals, the better route to go would be a commercial loan (lower down payment) than a traditional mortgage.

I can offer select services remotely up and down the state for a fraction of the cost of traditional management.

Not everyone is in a position (economic, Marital, or otherwise) that allows them to execute a full-fledged "traditional" investment strategy. 

Unless their income or equity have increased substantially, borrowers currently holding this type of loan will have a hard time qualifying for more traditional refinance mortgages for similar amounts.