I went into my Verizon store today. They had 2 Droid X's on demo. One had .589 (never seen this before) and wasn't getting an update. The other one was .516 and sure enough as soon as I checked the updates it wanted to download .604.
Thrpey said they could flash it but they didn't want to risk breaking it since they didn't have any in stock.
Their excuse was that the update is only getting pushed to 2000 people at a time which is bs because I don't know anyone who hasn't gotten it.