If it's true, we'll likely know next week, as Oracle's OpenWorld conference begins. That is, if they can talk yet, or are willing to talk. I'm skeptical of either happening. The real crux of this possible bombshell news is that that pages at MySQL.com that host information on 6.0 appear to have been deleted. Browsing through the source tree, we see that 6.0 is also a seemingly dead branch, with its last contribution coming in June of this year. That's remarkably close to the time when the Oracle/Sun merger was finalized. I will continue to ask questions to those involved, but this initial look certainly seems to point all fingers at the death of MySQL 6.0.
Update: I stopped by the MySQL IRC channel on Freenode and pulled some info out of them. It looks like 6.0 is no more, but the ideas and plans for 6.0 will still make it into a future 5.x version. So, 6.0 is kind of dead, but not really. The road map has been changed a bit, but MySQL will continue to improve. Far more info can be found at this blog.