What I'm saying though, is that its the way that green chilli taste changes after a lot of cooking in oil that gives that unique flavour - imparting it to the oil.
The reclaimed oil is one way of doing it, or you could try making it - theres even a couple of threads on here where people are suggesting making spiced oil.. but not mentioning fresh green chilli! What all of these recipes need is fresh green chilli.
If you don't want the final dish to be hot, then carefully score the chillis and tip the seeds out. Beleive me I've done this before and the final result, as well as several other characteristics, has had that distinctive taste you get from a take away.
If you want to fit my suggestion into your own 'scientific' method then try this: put 250ml SF oil in a pan, heat it up (but nowhere near smoking temp) then throw in about 25 stemmed, deseeded small green chillis that you bought by weight in the local indian shop. cook it so the chillis are rising and slightly bubbling for 35 - 40 mins, then either take the chillis out with a spoon with holes or strain.. Cool this oil and use it as the cooking oil next time you make your best 'nearest to the real thing' recipe - if you want to remain objective make one at the same time with normal oil.
I think you'll be surprised by the result.
By the way one more thing - I noticed theres a thread on veg ghee, some of you are experimenting. Have a quick search for veg ghee trans fats.. this stuff is generally though to be pretty nasty (and it falls under the new york trans fat ban so curry cooking is def still fine without).
I actually think the main advantage for the restaurant is that veg ghee saves them money because it doesn't have to be refrigerated - marginal effect on flavour and butter ghee or SF oil will do the same job in every case.