As I posted in another thread:
There certainly will be some 800m guys that can break 11 from the blocks, it isn't common though. I'm thinking maybe Amos who ran 44.1 in the Beijing 4x400m, he certainly has the speed.
Like someone said, Curtis Beach broke 11 and ran 1:47.
The argument before about 1500m guys is different. 400/800 guys like Amos and Berian are fast. Over 200m Amos has run 21.34. That strongly suggests sub 11. Even if you say he would run a faster 200m than 2x his 100m, he will still break 11, 21.34 ÷ 2 = 10.67. He has a lot of time to play with there.
Very few will break 11 but there will be a few that can break 22. *Many will break 22 at the elite level. There have been others like Amos who will break 11.