I just had an interesting idea for
Mastercoin Gateways.
You might be familiar with the concept of
Ripple Gateways.
The primary function of a Ripple Gateway is accepting Fiat from customers, and "converting" it to "Fiat IOUs" which are then sent to clients.
You can come into this Gateway, wire it USD, and get USD IOUs in return.
Well, we can easily translate that idea into trust-less Mastercoin Gateways.
A Mastercoin Gateway would be a business or entity that accepts fiat and sends back the same fiat in the form of a CFD or backed currency.
I call it "trust-less" because once the deal is finished, you no longer need to have any trust or relation with the Gateweay, unlike Ripple Gateways which require the Gateway to keep functioning because it
owes you money.
Real world Mastercoin exchanges could double as Gateways - regulation for these might vary, or might be the same, per state and regulatory environment.
What about a network of Mastercoin super-nodes gateways, not for Fiat but for adjoining the currently Bitcoin situated Mastercoin protocol, with other crypto-currency block-chains? This would facilitate distributed any-coin <-> any-coin trades, as currently roughly implemented for BTC <-> MSC. With this type of gateway, Bitcoin can continue its main lead as a store of value, even if other alts eventually prove better as means of exchange.