Rumor: iPhone 5S Coming in March?

Rumor has it that Apple plans to begin production of preliminary test builds of the next generation iPhone in March.

Jefferies analyst Peter Misek believes the next iPhone refresh will reach the mass market well before the one-year anniversary of the iPhone 5 launch.

Misek is among a long and growing list of analysts possessed of the notion that multiple iPhone refreshes within a calendar year will be the norm in coming years. According to published reports Tuesday, two new iPhone models may be tested in the coming weeks.

On rumors of an entry level iPhone, Misek said he expects a concentrated low-cost iPhone rather than a “cheap” one. Likely specs, according to Misek: polycarbonite case with 4″ non-Retina display and no LTE. We believe a new low-cost iPhone would increase Apple’s share, decrease GM, but have little impact on EPS.

For Apple, optimism about hot new mobile products can’t enter the market soon enough. Shares of AAPL tanked yet again today, falling below $485.

All told, Misek maintains a Buy price target of $800 for AAPL.