I know that Board minutes can be subpoenaed, but can the SAR Committee documents & minutes also be subpoenaed? Or, does this fall under Safe Harbor?

The short answer is "No;" both the SAR and anything that would reveal the existence of the SAR (as these documents would) are exempt from subpoena. Your bank would notify FinCEN and your federal functional regulatory agency of the demand and notify the court of your refusal, citing the appropriate law and regulation.

If this is more than a hypothetical, you may want to read the revised regulation and the supplemtary information that accompanied it late in 2010.

The BSA-AML Handbook, not updated since that date, does not include this information.