And I bought 3 other properties with a different deal structure, but also profitable. 

You can also personalize and theme larger homes better and seperate from the competition a bit. 3.

The cash flow is a bit sub par on this one and I anticipate some larger expenditures coming my way in a year or two so I'm contemplating this as an option.

A house that's similar, but 10% larger than another usually isn't worth 10% more.

This is where I would focus, as these are the same attributes that attracted those responsible for the larger projects like the Bellweather District you mentioned in your initial post.With your budget I would recommend NW Philadelphia (Germantown and Mount Airy in particular).

I am a little weary since I haven't done that before- not sure it would be enough to get me into buying portfolios or larger complexes though.. 

Many note funds take on debt from larger lenders or lines of credit against their assets.

Caveat is that you should be reinvesting those profits back into other smart investments so that you aren't missing out on compounding gains. 

All of your profit stayed inside the SDIRA and remained tax deferred there. 

I'm still in the process of growing my portfolio, but have heard others 1031 all their smaller properties into a larger building and have a property management company manage, OR, set up a seller financing deal with another buyer that gives you the cash flow you desire.