Out of curiosity, are there any calculations or instances showing the GDP of a planet, or a House/Clan region?
GDP can be estimated with few rules of thumb.
Usually total personal income is anything between 40% to 60% of total GDP of realm. Each realm has number of workers and number of supported persons (those not working for one reason or another). Assuming low unemployment this can be 1:1 but with gray haired society (or depressed economy) it can easily be 1:1,2.
We make simplifying assumption that 60% of realms money is income and society has support relation of 1 : 1,2. We assume that monthly average salary of realm is 1000 C-Bills.
Step 1) Calculate annual average income
12 months * 1000 C-bills as monthly average income is 12,000 C-Bills a year as income.
Step 2) Calculate effect of relationship between supporting workers and unsupporting population.
( 1 / (1 + 1,2) ) * 12,000 = 5454,55 C-Bills
Step 3) Calculate effect of share of total income as part of GDP.
( 100 / 60 ) * 5454,55 = 9090,91 C-bills / per annum as GDP per capita.
Step 4) Insert population of realm
Assume 10,000,000 inhabitants:
Total GDP is 90 909 090 909,090 C-Bills for this realm of 10 million inhabitants.
It is 90,9 billion C-Bills per year.
Now all you need to do is insert the average salaries and population sizes (with few necessary assumptions) of the different realms to see how it all looks...