Both of my Lexus LS400s (one was a 1990 and one was a 1991 - over 200K on each) still had a dark brown (not black) oil at the end of the 3000-4000 mile interval. Around 2000 miles, still looked like new oil. Last time the dealer said I could go 5000 on the Lexus oil change... I did and I checked it before I took it in... it was still full on the stick and it was dark brown and not black, even with 5000 miles on it. Something special about those 4.0L Toyota V8s.
My 4.7L Tundra was the same way. Now I have had some cars that the oil turns dark (chocolate brown) before 1000 miles.