So I'm actually doing the same thing bpage is (and I know him—and live down the street from him).
Wondering if this rig would work well with unRAID: https://pcpartpicker.com/user/charlestephen/saved/GyjnQ7
Case: Fractal Design Define XL R2
Motherboard: Asus X99-DELUXE II ATX LGA2011-3
CPU: Intel Core i7-6800K 3.4GHz 6-Core Processor
RAM: 4x Kingston HyperX Fury Black 8GB DDR4-2133 Memory — 32GB total
Storage: 4x WD Red 4TB 3.5" 5400RPM SATA 6Gb/s 64MB Cache; 2x Toshiba 2TB 3.5" 7200RPM SATA 6Gb/s 64MB Cache; 2x WD Caviar Blue 500GB 3.5" SATA Gb/s 16MB Cache
Power Supply: Corsair CXM 650W 80+ Bronze Certified Semi-Modular ATX Power Supply
Video Card: AMD FirePro W2100 2GB Video Card
I'm moving about 7TB of data from my Mac Mini/Pegasus RAID and will be running Plex and related apps like bpage (hey Brian!)