Uhm.. Your ideas aren't exactly new.. And in fact pose a counter-productive scheme..
Without identity verify or login, you can't exchange FOREX..
I think OP plans implement an exchange service which you can login and doing trading activity and also you can exchange instantly without sign up/identity.
Like you said it's not new and I personally pretty much found site which have these features. In OP plan case should be have a lot reputation, combined exchange+store. Also the security system must in high level.