This seems like something that any company with the capital to submit asset custodian paperwork (in whatever region they wanted to operate in) could set up, but is not necessarily in the interest of the DAO because assets purchased would concentrate in a single address. The person to do this would be a lawyer of some kind or a financial institution with existing licenses in their region imo.

Land and collectables are priced in Mana. Where would the dollar to mana exchange take place? Are you suggesting that the DAO becomes fiat exchange? Who would deal with chargebacks and customer support related to credit card payments? Would there be a markup on the land or collectable since credit cards take a fee just to transact? I can see why you might want such a thing, but this is crypto, and where we are going, we dont need credit cards.