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.
While this is probably technically feasible, it won't be high on the priority list for MSC implementation.
One of the main reason it was decided to implement MSC on top of BTC instead of a separate blockchain, was the snubness toward altcoins the btc elite had.