I don't see why the two "trusted" forum members would be willing to participate in this setup. If the OP turns out to be a scammer, their reputations would suffer, and they will have to perform work for less money than if they were offering escrow services on their own.
Maybe money (service fees) will motivate them or there will be no reason for anyone to volunteer for some business.
I have anther idea - maybe m4acker can escrow a large amount of money (x) to a trusted escrow on the forum. His website will have a program which will show live statistics of how much money the site is escrowing (y). There will be a cap for y, and always it will be y< x
Website users will have a tool to verify the total amount too (not sure how it will be done). If something unexpected happens from the OPs side then forum escrow will pay the clients.
I don't know maybe it sounds complex but at-least this could help in this situation and OP will not need to reprogram his site.