A 2-of-3 multisig escrow address with a hypothetical malicious escrow agent could conspire with one of the parties of the transaction to steal the coin in the escrow address.
I am not saying the OP is acting maliciously, however, based on his current reputation, it would be difficult for an experienced forum member to use the OP as an escrow agent.
Here is my idea -
OP can have two trusted user from this forum. Both these users will hold a key each and OP will have another key. If this is a 2/3 MultiSig then OP can not move the fund without another signature from one of these two users. For every transaction he needs one of them.
Obviously OP and other two users will need to be public (not necessarily to have their personal information in public) about their involvement in the project, and they will negotiate how much they want from the business.
I'll look into this multisig idea for reputation, i wanted to be personally involved in transactions as little as possible (because I need to work!) but will research the idea.
Without having enough trading history and good volume of the trade amount, I do not think anyone will entrust you as an escrow. In fact, you may even receive negative feedback as warning from the members of the community if you attempt to do such a deal without showing enough credibility.
Edit:
hypothetical malicious escrow agent
I see your point now. It's possible of course. Maybe not a 2/3 but another format which is safer enough?