MintDice

Only the gateways can be used to properly freeze assets, similar to any other currency on any other exchange?

There probably aren't too many economies that only apply to ripple without applying to other things as well. The one thing that Ripple attempts to do is create a sort of bridge between the cryptocurrency and fiat world, granted its a very tough problem to solve. A lot of industries were this is going to apply will be large banking and financial services. So perhaps you could figure out something in that niche, but that is a difficult one to enter without some capital and/or infrastructure in place. You could always attempt to innovate as well.