Shares of Sprint (NYSE: S) Nextel closed at $6.17 apiece on Tuesday, the lowest level since 1988 on the best day the street had in five years, and fell even further Thursday. At such bargain stock prices—the third largest U.S. wireless company has a market cap of $17.3 billion, or less than half what Microsoft (NSDQ: MSFT) is offering Yahoo (NSDQ: YHOO)—analysts are feverishly speculating the company’s fate.

AP offers a round-up of the rumors today:

—A Merrill Lynch analyst speculates that Deutsche Telekom (NYSE: DT), the parent company of T-Mobile USA, might consider buying Sprint to bulk up and prevent an escalation of flat-rate pricing in the industry.

—Carlos Slim, who operates the wireline and wireless networks in Mexico, might see Sprint as a way to get into the U.S. wireless market, WSJ reports.

—Verizon Wireless (NYSE: VZ) and various U.S. cable providers, looking to fight traditional telephone companies, are potential buyers.

—The company sells off its WiMax or Nextel networks.

—Spins off its WiMax network and merges it with Clearwire (NSDQ: CLWR) with the help of Intel (NSDQ: INTC), or other investors.

At the same time, some of these scenarios are seriously out there, and doubtful. This week, Sprint Nextel said it couldn’t easily be split off Nextel, which it bought three years ago. Bloomberg reported that Chief Network Officer Kathy Walker said separating operations would take longer than integrating them—Sprint’s technicians work on both technologies and it has combined network-monitoring operations. The AP also reported that a Stanford Group analyst doubts the company would be able to sell its Nextel-branded network because it’s bleeding the most customers.

Of course, there is one last option—Sprint will have to conduct a turnaround all by itself.