Well, for the forums, I don't think you would find much interest. I would say that most people here would rather use an escrow from the forums, rather than an online forum.
But that aside, what's the plan exactly? what is you're planning to support? every kind of transaction? or you're planning to limit this to SPECIFIC payment methods, or specific things (for example, only currency exchanges, as opposed to also supporting physical goods, digital goods, etc.)
Good questions. Starting narrow: currency exchange (USDT/fiat) first, since that's where the 'who sends first' standoff is most painful and the settlement is simple — either the fiat arrived or it didn't. Physical goods get messy fast (shipping disputes, condition claims), and digital goods have their own verification problems, so those would come later if at all. Payment methods: whatever the two parties agree on, the contract only touches the crypto side. Still early though, mostly thinking out loud at this stage.