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 5,300 rated companies, but they're just shy of superstardom. While all the attention might be focused on their five-star peers, we can find four-star companies that might be approaching greatness, including this handful:

  • China Sky One Medical (NASDAQ:CSKI)
  • China Yuchai International (NYSE:CYD)
  • Hudson City Bancorp (NASDAQ:HCBK)
  • Mirant (NYSE:MIR)
  • SuperGen (NASDAQ:SUPG)

Some of these names might surprise you. Hudson City Bancorp, for example, has been serving depositors in the tri-state area including New York, New Jersey, and Connecticut for more than 140 years. It was where I opened up my very first savings account many years ago. Almost great? Even familiar names can still offer some of the best opportunities. Perhaps we've just forgotten the potential they still hold. However, the 135,000-plus CAPS members chose these companies as less obvious sources for tomorrow's great buys, so let's see why they might merit your attention.

In the sight of greatness?
It has been little more than 20 years since Kentucky Fried Chicken dunked its first drumstick into a vat of grease just outside of Tiananmen Square, becoming the first American fast-food restaurant to upset the delicate balance that had ruled the Chinese diet for thousands of years. And it wasn't long after that when McDonald's erected its Golden Arches to serve double cheeseburgers and gut-busting Big Macs. According to one medical researcher, from 1985 to 2000, the number of overweight and obese Chinese children increased 28-fold, while an estimated one-fifth of the world's population that shops for extra-extra-large-sized clothes lives in China now. Coincidence?

Americans know a thing or two about obesity. The Centers for Disease Control says that on average we weigh 25 pounds more today than we did in 1960, but we also had a head start on the Chinese: Ray Kroc opened his first McDonald's in Des Plaines, Illinois, in 1955. I'm beginning to see a pattern here.

Though the Chinese might raise an eyebrow at how we sweat to the oldies with Richard Simmons videos, many Westerners might do the same at how the Chinese rely on traditional herbal remedies. But China Sky One Medical finds great success in traditional Chinese medicine, particularly with its four patch products that brought revenue growth of 240% for the latest quarter.

One of those patches is used for weight control: The patch is infused with saponin, a traditional therapy believed to regulate the excessive secretion of certain hormones while promoting others. Saponin gets its name from the soapwort plant, which is typically used to make soap. In the U.S., however, the Federal Trade Commission has waged a campaign against similar transdermal weight-loss patches that use sea kelp as their main ingredient and claim to "melt away" pounds. The FTC considers it a "red flag" for consumers when a company suggests you can lose weight by wearing a skin patch.

Yet China Sky One Medical, like American Oriental Bioengineering (NYSE:AOB) and Tongjitang Chinese Medicines (NYSE:TCM), sells its products primarily in China. China Sky One Medical has enjoyed greater than 100% compounded annual growth in sales over the past three years, while American Oriental Bioengineering has enjoyed similarly strong gains.

China Sky One Medical's success, particularly while the Chinese are becoming more concerned about their health and well-being, plus its latest acquisition means CAPS member DavidBear likes it as a stock to hold well into the future.

Chinese Medicine Company operating in China. Recently (December) took advantage of the economic crisis to buy a smaller drug company for ~$7M. I take this to indicate that the management is engaged. The P/E seems pretty low for an actively growing company. I like [the company] in the long term.

BCCanuckEST1980 believes the company offers a fundamentally cheap valuation without too much risk.

China Sky One develops and sells over-the-counter nutritional supplements and over the counter plant and herb based medicinal products in PRChina. The products have a range of uses from weight loss to pain relief to skin sanitization.

Stock is currently cheap based on fundamentals. Medium risk stock as you can expect wide swings in price range

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.

American Oriental Bioengineering is a Motley Fool Global Gains recommendation and a Motley Fool Hidden Gems selection. The Fool owns shares of American Oriental Bioengineering. Try any of our Foolish newsletter services today, free for 30 days.

Fool contributor Rich Duprey does not have a financial position in any of the stocks mentioned in this article. You can see his holdings. The Motley Fool has a gold-plated disclosure policy.