Thanks for your response givemedew, the X9SRL-F looks like a great option.
I have already picked up a beat-up Antec 1200, 3 x CSE-M35T and ICY Dock 6 x 2.5 + ultra slim ODD enclosure. I plan to move over a 3in2 cage from my existing build and have an old LSI SAS9220-8i I can pop in to allow for more drives. With the generous PCIe slots of the X9SRL-F I can add an additional LSI SAS9220-8i and graphics card down the road to finish wiring up the cages and improve transcoding.
Now I have to get after cleaning up the Antec 1200. The ebay listing mentioned that the case was not in the best shape, a massive understatement. Smells like it has been used as an ashtray for the past 10 years. I plan to scrub it as best I can and then spray paint and replace all the fans. It is also missing the PSU backplate so I'll need to figure out a replacement for that. I'll post pictures when I'm done.
Thanks!