It depends on who you are. If you are a government, for example, you can allow people to use bitcoin2 to pay taxes, and you can use it to pay government contractors.
I suspect some large companies could also do something like this. Amazon or Walmart, for instance. They could give discounts to people who use a digital currency they are trying to push, and that could be enough to bootstrap things.
I had those same thoughts when bitcoin first came out (or rather hit mainstream) and put them on my Bitrific blog, which I subsequently shut down.
A new government backed currency being disconnected from paper is one thing, but being disconnected from fractional reserve banking is another and likely to be met with very violent opposition if a target can be found.
There'd a have to be a total change in government policy for a modern day digital Lincoln greenback. I don't think the Corporatocracy would allow it to happen at this point. So bitcoin is the closest we can get to it - money for the people by the people (instead of money for the corporations by the banks with the help of government.)
I suspect some large companies could also do something like this. Amazon or Walmart, for instance. They could give discounts to people who use a digital currency they are trying to push, and that could be enough to bootstrap things.