Ukraine default scenarios (and debt restructuring) is now in the front line news, especially with IMF declaring then un-declaring its distaste for Russian position on EUR3 billion debt Ukraine owes Moscow that is due this year: http://www.reuters.com/article/2015/03/27/ukraine-crisis-imf-idUSL2N0WS1FO20150327. So much so, even Reuters are confused...
But here's the markets absent any confusion: Ukraine CDS are now trading with implied probability of default of 98.2%.
Which is, at this stage, only a question of whether or when the ISDA call the default.
Whether you like it or not, Ukraine needs to restructure its debts. Its economy cannot carry the interest burden and it cannot sustain any sort of recovery absent a significant debt writedown. Lending to the country to repay some of these debts is madness of highest order - so much so that even the IMF knows it. Even if Ukraine gets a massive writedown of debt, it will have years of extremely painful reforms ahead of it, and its economic development model will have to be re-written in its entirety. But at least the Ukrainian people will be able to think of this pain as not going to fund foreign legacy lenders. A small consolation, but a necessary one.