Ghenghis
Yes it has been done. The one I vaguely remember must be over 25 years ago and involved a UK research organisation. The drinks they provided were ethyl alcohol at the same strength as UK liquor, i.e 40% v/v, in units of 1/5 th of a gill, a wonderfully archaic English measure, but the unit of liquor in UK bars at that time.
The pilots under test were given a set routine to fly in the simulator and objectively scored upon it. Then after each unit and 20 minutes wait they were re-tested.
The results were mostly as predicted, i.e. the motor skill and processing ability reduced per drink. But the surprise was that the first drink actually improved the scores. Whether this was because the candidates were trying harder and still had residual skills, or whether it was a physiological effect was never proven.
The other interesting point found was that the decline in ability was not linear. Once you were over two drinks, the performance fell off markedly.
Now where that research is today I have not idea. A bit like the research into marihuana, when a mildly positive effect was found, the government withdrew funding and outlawed the research.