I seem to recall a recent episode of Gun For Hire Radio where guest attourney Evan Nappen described gun trusts as a possible shelter for ordinary firearms. In order to do this, however, the government would have had to succeed in reclassifying the firearms as destructive devices (class III, I think?). Then you would have the legal right to create a trust. (Disclaimer, I don't have any idea if I am correct on these details. It was just the impression I got from listening with a non-legal brain)
I'm just working from memory, here. I believe it was episode 84. The download page is here:
http://gunforhireradio.com/podcasts.html
I did a CTRL+F (find on page) search for keyword "Evan" and got the 8 episodes he appeared on. Episode 84 seemed to jive with the time of year I remember them discussing the subject. But you won't go wrong (and will probably enjoy) listening to them all.
I hope this is helpful
Erik