Can they be bolted together horizontally to form a block?

The  builder would need to fund horizontal construction including the land.  

You'd need to purchase the land on your own (through whatever financing you deem best) and then you can get a construction loan that is both horizontal and vertical to cover the build and reimburse the land purchase.

In an ideal situation, I would provide enough of a horizontal income stream that I can leave my full time job, and pursue my passion which is small scale farming.

Expanding horizontally is also my ultimate goal, by integrating the construction, property management and asset management as separate companies, managed under one umbrella company.  

I have 23 STRs and I manage them with a piece of posterboard with 23 horizontal lines and Post-It notes.

Construction loan could cover just the construction or I have an option to do both horizontal and vertical construction.

They open and close with the stick, no strings, and our cats don't wreck them getting in the window like the horizontal kind.

I've been using $150 sq ft for vertical and $140 for horizontal.

Depending on how bad is the foundation state (how many inches you have to correct), is very possible the sewer line will disconnect/break in the horizontal portions.