I don't think the government would allow Goldman Sachs to create a for-profit private currency. In fact, I am a little bit surprised that they've accepted Bitcoins to the extent they have. It might very well be that there will eventually be a total crackdown on private currencies. But I think that in general governments would view private currencies created by charitable organizations more benevolently.

How to get the whole thing rolling is a hard but perhaps not unsurmountable problem. The problem is of course that a currency that no one else uses is not very useful. On the other hand, if lots of other people use a currency then it's very useful. So currencies have a winner take all structure.

I can think of two groups that you would try to market this for. The first is altruists and charity organizations, which would have an interest in using the currency if they knew that that benefited another charity they trusted. The second is the people who are interested in Bitcoins for whatever libertarian or other reasons (minus the criminals).