@Chris Martin very interesting analysis.
I love these types of analytical discussions so I decided to take a look at the data myself!
Was interested to see if your assertion that CA buyers are more likely to 'park' money into properties held up against the relevant data. Interestingly enough I found that Californian are not paying any more for 2 to 4 unit buildings than local investors are on average. I found this by first normalizing the purchase price by number of units in the property, giving me a price paid per unit figure. Then I aggregated by year sold.
As for whether or not a builder can get $202 per sq ft on a SFR, I found that it is not the case. Over the past decade prices per sq ft on new construction SFR have gone up measurably, but it does not seem like $200/sqft has been reached in the Raleigh market.
Your guess as to when CA buyers purchased their properties is correct. The past 3 years account for a large percentage of 2 - 4 unit buildings procured by Californians. There was also a notable, yet predictable spike before the 08 crash.
Lastly, here is map with drop pins for all the 2 - 4 unit buildings purchased by Californians with corresponding location grades. Seems like most are located in B/C areas with the notable cluster located in a D area. This, I would argue, reinforces the assertion that Californians are in fact looking to invest in real estate for cash flow, not just as a wealth preservation vehicle.
Let me know if you any thoughts