JKM7's comment about needing better controls for a study are well stated.
For a good study, the people running the test will probably take pure (as pure as possible) Ethyl Alcohol, measure the exact volume, and mix it with something to make it a bit easier to drink (maybe 50:50 with water, for those who already drink Vodka). They'll probably want a number of test subjects -- although 'anecdotal' reports of only a few subjects may be of some value. They'll have to decide whether or not to use subjects who ARE taking anticoagulants or who are NOT taking anticoagulants (and, if the subjects ARE, there are a lot of other issues -- age, sex, current dosage of anticoagulant being taken, etc.) A good, scientific study could be a long process - and may not be a lot more valuable than doing a test on YOURSELF to see if you, personally, have an issue with alcohol's effects on your INR -- testing shortly after drinking (or even WHILE drinking) may show something, and a test or two, if an effect is seen, in an hour or a few (as long as changes are seen), may help clarify how YOUR body deals with alcohol and INR.
Even testing yourself may not be a reliable test -- if you drink with food, perhaps the food had some minimal short term effect on INR. The next time you drink, your body may react differently. What should probably be assumed is that the effects of alcohol on your INR are probably short-term; the probably won't show up on a test hours (and certainly not a day or more) later.
I haven't seen any reports of alcohol making an INR spike or drop dramatically. (If, for example, that bottle of wine -- or, being a bit more dramatic - that bottle of tequila, suddenly changes your INR from 2.5 to 6.5; or drops it from 2.5 to 0.6 - then there should be reasons to be concerned and to avoid alcohol). I don't think this is the case.
And, possibly because this effect hasn't been observed, researchers probably didn't see much need for spending the money that controlled tests would cost on research that really has little impact on how we live our lives. (And the drug companies couldn't develop a medication that they claim anyone on anticoagulants MUST take when they drink, so that we don't drop dead from a stroke or bleed to death, and charge $10 per placebo)
And Mecretired -- I don't think anyone gets rich doing this kind of research.