Good news and bad news for Research In Motion (NASDAQ:RIMM): The good news is that the stock rose 5% on Thursday — in fact, since Monday’s close, the stock is up more than 15% (though shares have given back 2.8%% in Friday’s trade amid the market’s selloff).

And the bad news? Well, how much time do you have?

RIM’s rebound is one of those Richard Farina moments — it’s been down so long it looks like up. The stock fell as low as $25.82 on Monday, its lowest level in nearly five years. Even with the rebound since then, the stock has fallen 56% in the last three months. RIMM is worth about one-eighth of its market value in August 2008, when the stock reached its its all time high of $92 a share.

So to many, this week’s rebound is little more than a dead-cat bounce. And that view is supported by the bad news that continues to come from the company. One of the few bright spots in its recent earnings call was that RIM had shipped 500,000 PlayBook tablets last quarter.  That was substantially above analysts’ estimates, and a welcome surprise given the tepid reviews that the tablet had received.

But “shipped,” of course, isn’t the same as “sold.” And sales may not be so hot. On Wednesday, even as RIM’s stock was bouncing back from the company’s dismal earnings report last week, Taiwan tech site Digitimes checked with RIM’s suppliers and found that RIM had revised its internal sales targets for the current quarter down to about 850,000 PlayBooks from the initial target of 2.4 million.

In other words, RIM think it will sell only a third as many Playbooks this quarter as it originally planned, which is terrible news, since the device was RIM’s best chance at redeeming its appeal to consumers. RIM has been stumbling in smartphones: The Blackberry is losing its appeal as the premier business phone and new versions are facing delays at a very bad time.

It’s not even so much that the Blackberry and the Playbook are bad products. It’s more that RIM is in a race with rivals that can move much faster. Apple’s (NASDAQ:AAPL) iPhone (now with iCloud!) is making inroads to corporate IT departments. Google’s (NASDAQ:GOOG) Android continues to grow its market share through lower-cost phones. And even Microsoft’s (NASDAQ:MSFT) Windows Phone 7 is expected to have the second-largest smartphone market share in 2015, thanks to Microsoft’s partnership with Nokia (NYSE:NOK).

A Canadian newspaper also reported this week that RIM had started laying off an unspecified number of workers – a sign that RIM is eager to shore up profits in the near term at the cost of long-term revenue growth. Some employees left without waiting for pink slips. A top marketing executive bolted RIM for rival Samsung Telecommunications.

Then there were the buyout speculation: Would Microsoft buy RIM and stir the Blackberry platform into the Windows-Symbian casserole it’s cooking with Nokia? After all, RIM’s stock is trading below 5 times its historical earnings (how many stocks representing a $15 billion market cap can say that?), and Microsoft might want access to RIM’s customer base.

RIM’s 50 million or so customers could help Microsoft build a critical mass of users to ensure it has one of the three top mobile platforms. But RIM is a different animal from Nokia. Most of Nokia’s customers are people who haven’t upgraded to smartphones yet. They’re not wedded to a particular smartphone platform. But Blackberry users may not take to Windows Phone 7 so easily. They may move instead to the iPhone or Android.

Dell (NASDAQ:DELL) or Hewlett-Packard (NYSE:HPQ) could acquire RIM, but such a deal would just buy it more time. Dell and H-P aren’t likely to become key players in mobile devices either, although they appear to be willing to spend lots of money before the reality sinks in. RIM could also remain independent and struggle to turn itself around on its own.

None of these options are very appealing. Research In Motion manufactured the must-have business phone for most of the last decade. Now, Wall Street’s judgment is that that era is ending. If that view proves right then, barring a buyout, RIMM’s bounce this week might be no more than a swan