It's interesting, because I have not heard of a civilian lab or company that claims to be able to recover data that has been overwritten, even once. If the technology existed, there's certainly a market for it. I also don't think the FBI has any technology not available to civilians. Their technical capabilities are vastly overrated. They can't even find a few high profile hidden services, even though there are known methods of identifying them. If you know of a company, I'll gladly submit a hard drive for analysis, after a single random write. The hard drive will be filled with millions of copies of a text file with a unique message. If they can recover a single one of those files they can provide the message.