Some companies are obviously great investments -- in hindsight. Sure, we should have bought Starbucks at its IPO and earned amazing returns over the years. Yet for every stock out there screaming "Buy me!" others simply give us a nudge and a nod. How can we tell tomorrow's obviously great investments from the thousands of pretenders?

The stars' walk of fame
On Motley Fool CAPS, these opportunities can be found among our four-star stocks. In CAPS' proprietary ratings system, they rank higher than most of the other 5,600 stocks in the CAPS universe, but they're just shy of superstardom. While all the attention might be focused on their five-star peers, we can sift through CAPS to find four-star companies approaching greatness:

  • CV Therapeutics (NASDAQ:CVTX)
  • Enterra Energy Trust (NYSE:ENT)
  • Goldcorp (NYSE:GG)
  • Fujifilm (NASDAQ:FUJI)
  • Nevsun Resources (AMEX:NSU)

Some of these names might surprise you. Fujifilm, for example, has been challenging Kodak (NYSE:EK) in the film business for years, and its foray into pharmaceuticals, though seemingly quixotic, may transform the industry. Almost great? Even familiar names can still offer some of the best opportunities. Perhaps we've just forgotten the potential they still hold. The 105,000-plus CAPS investors have chosen these companies as less obvious sources for tomorrow's great buys, so let's see why they might merit your attention.

Adding fiber to your diet
Like grains of sand on a beach, small mining companies dot the landscape, and many have little chance of developing successful projects. Investors have been burned before, and they remain wary -- though they do seem to keep coming back. Nevsun Resources has at times seemed like it might burn the hands of its investors, as numerous financings have diluted ownership stakes. Yet it also holds the potential to reward them if it can pull off a successful financing to carry it through to production. It may have done that.

Nevsun is a gold-mining company with a single mine in war-torn Eritrea (located across the Red Sea from Saudi Arabia and Yemen). Getting permits to dig in the country has been exceptionally difficult, but this past January, the government issued Nevsun a permit for its Bisha project and has also come up with the financing for its stake in the mine. The Eritrean government has taken a 30% stake in the mine and secured a loan from China's export-import bank in the amount of $60 million to pay for it.

Obviously, an investment in Nevsun carries with it some substantial risks. But the Bisha mine is said to be one of the largest undeveloped gold and base metal deposits in Africa, with a reported 1 million ounces of gold, 9 million ounces of silver, 747 million pounds of copper, and 1 billion pounds of zinc. If Nevsun is able to successfully exploit its position there, it could reap substantial rewards for itself, the Eritrean government, and investors.

Investors like CAPS player handagith believe that Nevsun's shares have been beaten up because of its Mali mine (which it has now sold), but that the prospects for Bisha make it an investment that, well, anyone could run:

Great property, mining license, and gov't investment in Eritrea. Hammered over their mismanagement of marginal Mali mine (600/oz cost). At 1000 gold, one would think that even monkeys could turn this one around.

Yet that mismanagement also has some top-rated CAPS All-Stars, like shpacr, seeing Nevsun as one of those companies that could burn an investor's hand again:

"Marginal" mine in Mali (the company's OWN wording) that requires an 80 MILLION writedown? Other "significant" mine is in Eritrea. Me thinks that if this company ever DOES start to make money from these mines, the African warlords will seize them. Not exactly where I'd want to have my money tied up.

Certainly, any investors establishing a position would need to do so with eyes wide open about the risks that abound.

A great opportunity for you
You've heard directly from CAPS players on Nevsun Resources, but do you agree? Is Nevsun, or any of these four-star stocks, still investment-grade material? On Motley Fool CAPS, you can give your input, which ultimately influences how they're rated. Outperform or underperform, near-term or well in the future, your opinion counts.

Sign up today for Motley Fool CAPS -- it’s completely free. Let's us hear what you have to say about the great (and almost great) companies that interest you.