My main job is running my investment holding company, so I'm familiar with public and private market investments but new to RE. 

We use a combination of HML and our private investor network.

I only qualify for about $500,000 with my W-2 income.Without getting a private investor, is there anyway I can prove previous rental income in order to use the potential rental income to qualify for the loan.

When a property is sold or otherwise transferred, it often undergoes a reassessment of its value.

Quote from @John Williams: Has anyone been on the lender side of private money and had a bad experience that they are willing to share?

So true my Dad started a company in CA in 1980 called Cal Wrap the all inclusive DT had just come out and we only wrapped PRIVATE MORTGAGES  never bank mortgages.

They would not be offering you a hard money loan (loan based on the hard asset) and instead they are lending to you as a traditional lender with private money.

Leverage your W-2 income for better loan terms, explore private/hard money for off-market deals, and network with investors to expand your deal flow.Good luck!

An agreement would be signed, and the property would be sold in 5 years and proceeds split up appropriately.

The financing structure includes a hard money lender holding the first lien and private money lenders holding the second lien.