Cramming 14+ drives into a case and getting a motherboard to support them all simply isn't going to happen unless you start looking at enterprise class server boards which would torpedo your budget in a hurry. The parts that you list for the most are solid but there are some changes that I would recommend:
1) The motherboard you selected is nice but in all honesty for the build you're describing I don't see you using all of the extras that it comes with that are more geared towards extreme overclocking and other performance enhancements. I would instead suggest a Gigabyte GA-Z77X-UD5H
for $200. This will more than serve your needs and serve as a good base platform although in all honesty an ASRock Extreme4 will also serve your needs just fine.
2) The PSU is nice and a pretty good base although 750 watts is a bit of overkill it's not too far overboard. You might want to save a bit more but keep the same features with a Seasonic M12II 750 watt modular PSU
3) You're going to need a controller card or an enclosure, short of going with an enterprise class motherboard which would also require investing in a Xeon processor there aren't any consumer grade boards out there with as many SATA ports as you need.
4) You're way overspending on RAM. Even with extreme video encoding you're not going to see a difference between DDR3-1600 RAM and DDR3-2400 RAM.
All of that being said here's what I would recommend for a build:
CPU: Intel i7 3770K
Motherboard: Gigabyte GA-Z77X-UD5H
RAM: Kingston HyperX 2 x 8GB DDR3-1600
GPU: Gigabyte Radeon 7950 3GB
SSD: Samsung 840 120GB
PSU: Seasonic M12II 750W
Case: Fractal Design Define R4
Enclosure: MediaSonic 8 bay enclosure
Total build cost (not including taxes & shipping): $1,505.92