When I moved my aircraft to the N reg my daughter, who is a solicitor, looked at the various trusts on offer from a legal point of view. The one she liked was Optimus Fuga Pactum. I would suggest that you have a legal expert look over any trust before you proceed - at least one trust will not let you see the trust wording before you pay for it!
There is good info on N registered aircraft at peter2000.co.uk