According to KenRockwell, the 5D Mark III successor 5D Mark IV is rumored to be announced on March 17, 2015, and the price for body only will be $3,799.00. And it will be released in late April, 2015.
According to previous rumors, this seems make sense, most rumors said Canon 5D Mark IV will coming in early 2015.
Here are more specs for 5D Mark IV according to KenRockwell:
36 MP CMOS. 14-bit linear ADC, 16-bit data pipelines, as the D3X. 12-channel parallel readout.
Full frame (23.9 x 36mm)
50 ~ 204,800.
98% coverage. 0.72x with 50mm lens. 18mm eyepoint.
65 Points. Fine-tuning, if you have slight errors with certain lenses.
1/8,000 ~ 30 sec, bulb. Carbon fiber and Kevlar, tested to 150,000 cycles. Flash Sync: 1/200.
JPG, and/or CR2 raw.
3.2,” 1,280,000 pixels. HDMI HD output.
Yes, electronic virtual horizon.
Two CF slots.
Rated for 1,250 shots.
5.6 x 4.8 x 3.0″ (142 x 123 x 77mm).
30.0 oz. (850g) with battery and SD card.
27.3 oz. (775g) without battery, card, strap, monitor cover or lens.