Some companies are obviously great investments -- in hindsight. 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 5,400 starred companies, 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. Here are a handful.

  • Abraxas Petroleum (Nasdaq: AXAS)
  • Cummins (NYSE: CMI)
  • Global Ship Lease (NYSE: GSL)
  • Royal Bank of Canada (NYSE: RY)
  • SatCon Technology (Nasdaq: SATC)

Some of these names might surprise you. For example, Royal Bank of Canada and its Canadian peers haven't faced any trouble with the housing market. Less than 1% of all Canadian mortgages are in arrears, compared with 1 in 492 of U.S. homes in foreclosure. Maybe we should look at modeling our financial system after the one in Canada. Almost great? Even familiar names can still offer some of the best opportunities. Perhaps we've just forgotten the potential they still hold.

On the other hand, engine maker Cummins has enjoyed the rebirth of the auto market here at home and the tremendous growth under way in China. It's also getting a boost from its 30% share of the power generation market, and its stock has more than doubled over the past year.

Because many in the 170,000-plus CAPS community have chosen these companies as less obvious sources for tomorrow's great buys, let's see why they might merit your attention.

In the sight of greatness?
Even though its third-quarter financials came in below analyst expectations, Abraxas Petroleum reported a loss that was narrower than a year ago and its shares are trading at their highest levels in the past 52 weeks. That's a perfect opportunity to cash in, and Abraxas announced not one, but two stock offerings to sell up to 18.5 million shares to pay down debt and expand its capital spending program.

As many others before it have done, notably Chesapeake Energy (NYSE: CHK) and EOG Resources, Abraxas is focusing more on its oil reserves, with half of its increased spending this year targeting oil. It has stakes in the growing Niobrara region, as well as the more established Bakken play, factors that will serve it well, according to CAPS All-Star TMFBabo.

I do like that Abraxas has been shifting production to oil, which makes more economic sense right now. Current production is 65/35 gas/oil, but the target is 50/50 in the future. ...

Much of the potential here comes from possible reserves. The unrisked value of $31.35 shows the maximum upside case. I do expect the $3.31 per share proved reserves to grow over time, as more of its acreage is developed.

Dirt cheap?
The glut in dry shipping vessels has done more than make the Baltic Dry Index a relic for predicting the economy. It's causing dry bulk shippers like DryShips (Nasdaq: DRYS) to enter the oil market and Diana Shipping to become a container shipper like Global Ship Lease. The BDI has fallen by nearly half over the past few months, and capsize short-term charter rates are a quarter of what they were then.

A booming container ship market should point to better economic trends, and Global Ship Lease had a 100% utilization rate in its latest quarter because it didn't have any ships in dry dock. CAPS member MajorBob04 expects the shipper's stock to continue to rise -- it has nearly quadrupled over the past 12 months -- so long as the economy continues to expand.

You can tell us on the Global Ship Lease CAPS page whether dry ship companies like Diana will hurt its prospects for growth.

On the level
According to market researchers at TrendForce, the prices of global solar cell modules are expected to fall to just $1.10 per watt, which should pressure prices throughout the industry. SatCon Technology is a utility-scale component maker for the alternative energy industry, so it could capitalize on these trends as falling prices benefit larger projects because of economies of scale.

With 95% of the CAPS members rating it picking SatCon Technology to outperform the broad market averages, it seems they're expecting larger-scale growth, too. And to be sure it doesn't get bought out from beneath them, management has initiated a shareholders rights plan that will heavily dilute anyone that acquires as little as 5% of the company's stock.

Follow SatCon Technology on the Fool's free portfolio tracker.

A great opportunity for you
Investor sentiment suggests these four-star investments still seem to be on their way to five-star greatness, but it pays to start your own research on these stocks on Motley Fool CAPS. Read a company's financial reports, scrutinize key data and charts, and examine the comments your fellow investors have made, all from a stock's CAPS page.

Sign up today for the completely free service and let us hear what you have to say about the great and almost great companies that interest you.