I understand what you are saying about the impact it could potentially have on the community, but the ATF is going to do what it wants to do either way. They might decide a sign-off is still necessary even with a trust.

As far as the lawyers go, what you just said is that it is basically a crapshoot if you are going to get a good trust and if the lawyer knows anything about NFA items.
How do you know the lawyer you have mentioned didn't google NFA trust info, find out the information on the net already out there and say he knows a lot about it and would gladly charge you $2500 to write one up?