To spot not-so-obvious opportunities in Gartner's recent tablet forecast, investors might want to look beyond comparisons between Apple's (Nasdaq: AAPL) market-leading iPad and Google's (Nasdaq: GOOG) up-and-coming Honeycomb version of its Android operating system.

Gartner thinks Apple's tablet market share will decline from 83% to 47% by 2015. The biggest gainer is expected to be Android, moving from a 15% market share to 38% in 2015. Research In Motion (Nasdaq: RIMM) is expected to place a distant third in 2015, with a 10% market share.

The number of tablets sold is forecasted to jump from less than 18 million in 2010 to 294 million in 2015. But don't weep for Apple; Gartner expects the number of tablets it sells to increase by more than nine times through 2015.

Spending on tablets will increase at an annual average pace of 52% through 2015, according to Gartner. Companies don't have to be the market-share leader to take advantage of that kind of growth. That makes Gartner's forecast good news indeed for Android tablet makers -- Motorola Mobility, for example -- and Research In Motion.

But let's look past the obvious. It's also good news for component suppliers that were left out of the iPad. And that could point to an opportunity for long-term investors to get good deals on component stocks.

Two examples are NVIDIA (Nasdaq: NVDA), which makes mobile processors, and Atmel (Nasdaq: ATML), which makes touchscreen controllers. Both companies' products have received positive reviews in the industry.  Gartner's projections could even be a plus for the riskier Marvell Technology Group (Nasdaq: MRVL). Research In Motion has long been an important mobile customer, but it's not clear whether Marvell can maintain its share of the wallet at that significant account.

All three stocks are trading at a discount to mobile-processor winner ARM Holdings (Nasdaq: ARMH), based on forward P/E ratios (see table). What's more, despite very attractive prospects in large growth markets, both Atmel and NVIDIA don't trade at a large premium relative to the larger semiconductor industry.

 

Forward P/E Ratio

Atmel

18.5
ARM

49.1
Marvell

9.9
NVIDIA

18.9
Semiconductor Industry

14.9

 Source: CNBC.

Foolish takeaway
It's tough to make accurate predictions about a nascent market. However, the important takeaways from Gartner's forecast are not exact figures. The market is forecasted to grow explosively through mid-decade. Apple, Android, and Research In Motion are expected to be the market-share leaders. Long-term investors could do well with discounted semiconductor plays on these themes.

To stay updated on all things tablets, add any of the above companies to your watchlist: