A decade ago, investors who wanted to put money into China, Brazil, Latin America or other now-popular emerging markets weren't seen as contrarian -- but crazy. But after years of growth and massive investor inflows, many once-emerging markets have, in effect, emerged. All now correlate more closely with the S&P 500, negating the benefits of diversification many emerging market options once offered.

But for stock investors looking to selectively add risk, there are a host of new investment destinations, many now referred to as "frontier markets," which exhibit many of the characteristics Russia, China and Brazil did years ago, including political instability, destructive interventionism and uncertain growth. And while those risks may turn off many investors, many of these areas have demonstrated recent strength, and are thus are worthy of consideration.

One area investors typically overlook (other than Israel) is the Middle East, especially in the wake of unrest in Syria, Egypt, Libya and Bahrain.

Yet Egypt's stock market now sits at its highest level since last July, helping to push shares of Market Vectors Egypt Index ETF (EGPT), the only domestic fund to focus on the volatile region, up more than 45% in 2012, far outpacing even strong U.S. returns.

While unquestionably unstable, the news from the troubled Muslim state has improved. Parliamentary elections held in January paved the way for civilian leadership to be in place by June. The country is expected to receive a $3.2 billion loan from the International Monetary Fund in March, helping to assuage fears of a sharp devaluation of the currency. Weighted towards primarily mid- and small-cap financials (38%) and telecom (19%), the ETF offers exposure to 28 Middle Eastern firms, none of which are traded in the U.S.

Vietnam's stock market, which didn't even exist in 2000, sank 66% in 2008, gained 57% in 2009 but never fully recovered pre-collapse levels, even after we highlighted the investment prospects in this space nearly two years ago.

Yet in recent months there are signs prospects have improved. Inflation, which reached 23% last summer, has since moderated to 16%. The country's main stock exchange is up 20% this year, yet only trades at 11x earnings, below other Southeast Asian markets, let alone the US. Franklin/Templeton's (BEN) Mark Mobius is among the notable investors allocating to the country.

And while Vietnam is unquestionably a volatile and dangerous place to invest, so was China back in the early 2000s, when problem loans at state-owned banks caused most investors to pass on putting money to work. Many of those banks became the decade's hottest investments. Market Vectors Vietnam ETF (VNM) is the only pure-play ETF focusing on the south Asian country, holding nearly 44% of assets in financials like Vietin Bank or JSC Bank, none of which trade in the U.S.

After well over a year of bailouts, street riots and economic implosion, Greece has become nearly a slur term among American investors and lawmakers alike, who frequently point to the beleaguered European nation as a textbook example of government's fiscal irresponsibility. "Stop spending now, lest we end up like Greece," so the refrain goes. With a sovereign default now almost inevitable and the Athens Stock Exchange having hit an all-time-low of 630 in January (it traded above 5000 in 2008), Greece's economy is in shambles. Who would want to invest there?

Investors with an appetite for risk might find the risks are worth the potential reward. You can get exposure to the troubled country through the Global X FTSE Greece 20 ETF (GREK), whholds 32.1% of its assets in much beleaguered financials. That includes an 11.4% allocation to National Bank of Greece, which now resembles a penny stock and also trades in the US. Consumer discretionary (19.2%) and consumer staples (14.4%) round out the undiversified fund, which holds only 20 securities and closely tracks the Athens market.

Despite the steady stream of worrisome news, the fund has risen year-to-date by over 20%, more than doubling the return of the S&P 500.

Highly doubted and dangerous, the new emerging markets might end up surprising us all, just as Latin America and the BRICs have over most of the past decade.

—Jonathan Hoenig is managing member at Capitalistpig Hedge Fund LLC