SupplyLas Vegas is unique because it is a tiny island of privately owned land in an ocean of federal land.

Nothing tiny (no legos!).

These markets often have strong population and job growth and strong rental demand.But the reality is that even in more affordable markets like Columbus, you'll need about $50k-60k household income just to qualify for a conventional investment property loan (this assumes good credit and reasonable debt).

Between July 2009, and July 2010, the couple used more than $761,000 from this hidden account for payments on an American Express credit card; car loans for a 2006 Range Rover, a 2007 Bentley Continental, and a 2008 Rolls Royce Phantom Coupe; household expenses; legal expenses; department stores purchases; and a bulk gold coin purchase.

San Diego’s average house hold income is about what you stated, but the median is a surprisingly low (considering US news and world report lists it as the most expensive US city) ~$100k.  

If so, then they are not considered real property and you are dealing with the land value only.If they are stick built tiny homes on foundations, then that is something else.

Conversely, the number of small-multi family properties being built is a tiny tiny fraction of the number built from the 1950s-1980s in cities like Phoenix and Mesa.

I understand that the average household net-adjusted disposable income per capita is USD 20 519 a year.

Those are tiny, tiny obstacles compared to where this process succeeds or fails, and that is with the contracting. 

As for tiny homes, they aren't considered real property and don't add value to the property.