I think everyone is to fixed on the US dollar.
Even with a DVC/$ service most of the planet would need a $/useful service.
What we need is a DVC/useful exchange. Like localbitcoins.com .
That way everyone can get involved.
ThinkI
I'm not in the US. Views above are in context of relative types of exchanges not overall preferences, and I don't think there's enough 2-way interest yet to sustain an exchange. But I'm not against anyone testing ideas if I'm wrong.
Something like a work/bounty exchange and something like localbitcoin would be my top picks for useful.