In today's markets, the landscape changes quickly. That's particularly true for the booming Chinese mobile communications market, as China Mobile (NYSE:CHL) has discovered.

A little more than three months ago, I pondered what lies ahead for China Mobile, examining how a rising proportion of rural subscribers, and government efforts to prop up competitor China Unicom (NYSE:CHU), might affect its business. Since then, China Mobile's stock has soared another 50%.

Then Foolish colleague Tom Taulli and I debated the Chinese giant's valuation and prospects. Tom made great points about the effects of adding lower-spending rural subscribers, but China Mobile has made up for voice revenue declines so far, and kept average revenue per user steady, by growing revenue from value-added services.

Even with the longer-term concern of diminishing growth, I consider China Mobile a great company. I even included the company as part of a terrific trio of stocks on my fantasy pick list. But as shares continue to soar, I see less opportunity to get a great company at a great price.

Fundamentally, China Mobile hasn't wavered. But the stock continues to get more expensive, as pressure increases on China Mobile's 20%-plus earnings growth. Catalyzing events such as the pending announcement of 3G licenses may kick growth up to a new level. But government control in the sector could do just the opposite, if the nation's Ministry of Information Industry should want to further balance the telecom market.

Additionally, China Mobile has remained largely focused on its home country, while other international plays such as VimpelCom (NYSE:VIP), Vodafone (NYSE:VOD), and America Movil (NYSE:AMX) have already garnered significant exposure to high-growth, emerging markets outside their native borders. In the longer term, China Mobile will have to pick up the pace of expansion to keep a company of its size growing.

So as China Mobile shares continue to soar, the higher price leaves less room for opportunity. The stock may have been screaming "Buy me!" at $51 per share last month, but that sound is now fading in the distance.

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Fool contributor Dave Mock could swear that new BMW screamed "Buy me!" to him yesterday. He owns no shares of companies mentioned here. Dave is the author of The Qualcomm Equation. China Mobile is a Global Gains recommendation. Vodafone is an Inside Value recommendation. The Fool's disclosure policy attended Burning Man, but what happened there, stays there.