The plan to elevate Palm (NASDAQ:PALM) has come full circle. Products chief and executive chairman Jon Rubinstein yesterday replaced company co-founder Ed Colligan as CEO.

Colligan will leave with a list of accomplishments. He helped introduce the world to the PalmPilot, which revolutionized the handheld computing market. And he was COO of Handspring when it introduced the Treo, forerunner to today's top smartphones from Apple (NASDAQ:AAPL), Nokia (NYSE:NOK), and Research In Motion (NASDAQ:RIMM).

Still, this change is overdue. Rubinstein, brought in by investor Elevation Partners two years ago this month, has unleashed his signature product -- the Pre -- to a receptive market. The device has already set sales records for Sprint Nextel (NYSE:S).

Interestingly, good sales data may not be enough: Shares of Palm were down 7.7% since Friday's close, before rising on today’s CEO news. Investors apparently want to see either (a) iPhone-sized sales, or (b) more breakthroughs. The latter seems more likely.

This is good news in a sense. Rubinstein is a proven innovator, having first led the iPod and now the Pre to commercial success. But investor expectations may be too high. Even after the recent pullback, Palm is up more than 500% since early December, thanks to nothing more than the promise of Pre.

Rubenstein's troubling task: Create further shareholder value for a stock already trading in the market's nosebleed section. At these highs, no amount of innovation may be enough.

Get your clicks with related Foolishness: