Any way to take the bitcoins out of the U.S. ? Tax Free?
You can take Bitcoins anywhere you want.
In fact you don't even need your wallet.
All you need is the private key.
As to the second part of your question:
Are you looking for a way to take the coins out of the country?
or
Exchange them to fiat "tax free"?
If it's the first then read my first comment,
if it's the latter, depending on how many coins we are talking about here, unless you deposit the fiat currency in a bank, then there is no way for the gov to know you have ANY cash on you (unless you go around telling people).
EDIT: You will need to go through Dark Markets to exchange coins to cash.
That being said, I think it is a bad idea trying to fool the government.
I do not agree with taxation (on my hard earned money) but then again I do not agree with breaking the law.