We replaced an old rotting porch with a larger wrap around porch and staircase.

Most will require a 20-30% downpayment.For mid-sized loans ($5mm+) they may allow you to bring in some equity, but will require a certain percentage to be from the Key Principals (guarantors) and will require about 10% liquidity to be maintained through the loan term.How large is the loan?

You might contact the lumber companies, as they are important parts of building large numbers of homes and might be willing to tell you who their larger customers are.

On deals where I purchased from the MLS, I either bought after another buyer did not perform and got a better price or I tore the house down and built a new larger one in a high end area where the cost at purchase was basically my land cost plus cost to demo and where I could build for under $200 pSF and resale for over $750pSF.

If you're in an area that is appreciating, you can even consider a medium-term hold on the BRRRR. 1031 it in the next 3-5 years for example, into a larger property.

Dan,A good way to start is find a home in an upcoming area that offers a larger lot so you can add rooms/sqft. 

I just completed a Cash Out Refi on the California property and now have 200,000$ Liquid cash, as well as additional 50000K liquid cash for reserves/emergency funds etc.

A duplex or two is fairly easy and as you get your systems in place it will make the leap to larger multifamilies much easier.

I am seeing the bulk of developments in larger metro areas. 

When we say that MF is better, it is talking about larger MF.