hmm....u know, 5 years in Florida and I never really bothered to figure out how long an international or Indian license is accepted for there....
However, I have shown them both to the cops on a couple of occasions before I got my FL license.
Interestingly enough, one time was when I had
just bought a car in Orlando (2nd hand - 'twas a 1990 Chrysler LeBaron GT) and was driving it back to my college town of Melbourne (remember, Florida, not Aussie-land!

). I had a temp, cardboard plate on at the time, and the cops pulled me over coz the dam' plate had fallen
off somewhere on the highway! Luckily, I had the paperwork with me, but only had my IDP and Indian license with me (since I hadn't yet applied/tested for a FL one). They accepted it and let me go, but told me to get an FL license ASAP.
Now I would say this was pretty lucky, since cops in FL are not always lenient. As someone mentioned earlier, it can help to have only a foreign license on you, since they wouldnt know how to slap a penalty on it! But, of course, you can only get away with this so much.....