Which would you rather go down for: destruction of evidence, or what's in your hard drive? I'm asking a technical question, not a legal one. There are many instances where this would be preferable than giving up the data.
If someone released such a tool, the feds would make sure to clone your hard drive before supplying the password to it, or write a patched version of the tool that reads it to remove the disk wiping call.
Probably not the best idea.
Hiding the partition or otherwise making the encrypted data hidden is probably your only bet.