The white record is 10.00 held by Marion Woronin of Poland. His time is rounded up from 9.99+.
It is definitely possible for a white man to run under 10. I believe the progress of white sprinters was arrested during the 90s due to societal forces. Whites will probably never threaten the WR, but they could be better than they have been during the last two decades. We are just now beginning to see the reversal of that trend and I expect a white man to break 10 within the next decade.
Matt Shirvington could have done it years ago, but he squandered his career. The lesson of his career is that all promising Australian sprinters need to get the hell out of Australia immediately.
Currently the fastest white man is Matic Osovnikar from Slovenia. Craig Pickering from the UK is right behind him and a potential sub10 prospect.