apparently there is an article on using trusts for NFA transfers in the Feb. issue of SAR.
Thanks Mike for the transfer info and I found a link to the article: http://www.terma-nator.com/images/guns/sar-trust-article.pdf
It says that if your state requires trusts to be registered then you must do so. Some states like Florida have no fees, so it's a free ride. Not entirely sure about MA though. The Mass. Sec. lists fees for "trusts" but maybe there are different fees for different trusts.
Question pending: What are the fees, if any, to establish a trust in Mass. that will be recognized by the NFA.