The Oxford Institute for Energy Studies has an in-depth piece out on the cost of LNG plants, looking in detail at the drop in LNG construction costs and how maintainable the falls are in construction costs:
As you can see, the Australian plants dominate the top of the cost table, with many of the more recent plants in the US being a fraction of the cost of the Australian plants:
The good news for existing LNG plants is that the falls in construction costs are not as steep as they look. Oxford adjusts for the two key factors of (1) whether a new or expansion (2) if the project is for lean gas (without liquids) or rich gas (gas with lots of condensate or LPG) then many of the Australian projects aren’t as bad as they may look above. The Australian projects generate lots of liquids which offset the higher cost of gas production.