Construction cost vary depending on location and type of design and finishes.  

You might try doing a quick look around.There are entities out there like Linwood Homes that offer a wide variety of "pre-constructed" homes in a wide variety of style.Obtain the land, do the site work, have a general contractor do the assembly on site...You might be quite surprised at pricing and diversity of designs.

The quality just wasn't good and even though the samples they have posted seem to depict the level of creativity and quality of design, the end product was nothing like it.

Hi BP Community, I'm looking to add both space and value without developing into the yard.Can anyone provide a referral or recommend a professional remodeling contractor whom specializes in the construction and engineering of design/build homes?

I suggest making your rental just a tad bit better in terms of design and finishes in your local market.

My hope is to capitalize on my knowledge of designing great spaces to buy properties, make small changes that increase value, and rent them out in the competitive market. 

To answer your question, I would meet with both type of designers.  

I think we will have to make it a little clearer the type of home we are interested in purchasing not the type of design we will do in our own rehabs.

Having these skills and basic knowledge was very helpful for working construction this last summer and I believe it will help me achieve my goal of designing and building my personal home in the future. 

Pinterest is full of designers and people with vision.