Wall Street Journal article says:
As the bailout standoff between Athens and its creditors escalates, some European officials are suggesting something that was once unthinkable: Let Greece keep the euro currency even if it defaults on its rescue loans.
It goes on:
The idea of keeping Greece in the euro despite a default was briefly discussed by senior officials from eurozone finance ministries last week, although many of them harbor serious doubts about if it would work, according to people familiar with the talks...
Any scenario where Greece fails to secure new funds from its international creditors would likely see the government issue a sort of parallel currency to pay wages and government contractors for some time, even as it keeps the euro as its legal tender, experts say.
More at the article, which may be gated: Europe Asks if Greece Could Default Without Exiting Euro