Would something like this worK? The ikea site isn't letting me buy that one.
It's metal and sturdy. It also makes your computer look like it's levitating. Works great with the Fractal Design R5, but that's exactly as wide as it will get.
I ended up buying this from Amazon, due to also having carpeted floors in the office:
Works quite well.
Yes, I'd go with NAS-based drives such as the WD Reds or Seagate NASWare or Hitachi (forget what they call it).
I'm not entirely convinced that the WD Red vs Red Pro is actually worth it. The claim is that there's greater technology for larger sized arrays (i.e. 16 drives)...however, at the extra cost, I'm wondering if it isn't cheaper to get the regular Reds, let them be covered by warranty should they fail, or when it does fail out of warranty, cheaper to replace...Personally I think the Red vs. Red Pro is more marketing and less proven technology improvement(s). I'll defer to smarter people to educate me on this in case I'm over simplifying it or completely misunderstanding the differences between them.
Beyond the available SATA ports on that mobo you'll likely want to consider an HBA or RAID adapter of some kind. If you're going to use FreeNAS then the LSI 9211-8i is highly recommended flashed to IT mode with v16 firmware. You can usually find them on Ebay for about $100.
I think it should be enough. I've got 16 HDDs in my setup and only a 500watt PSU...so adding in 4 more with the additional 150watts shouldn't be an issue (I think).
With respect to the case/chassis, I'd suggest you look at eBay for an old Supermicro or Norco case. Sometimes you can find them cheap including the swappable drive trays. Even though these are usually rack mounted, you don't have to. You can just set it upright light a tower or use one of these to keep it in position.
I'm using this to hold the CPU: Syba Steel Computer Stand for ATX Case with Adjustable Width and 4 Caster Wheels - SY-ACC65057 https://www.amazon.com/dp/B006V9AUMC/ref=cm_sw_r_cp_apa_Wq0uzbBGVD34R
https://www.amazon.com/Syba-Computer-Adjustable-Sy-Acc65057-SY-ACC65057/dp/B006V9AUMC would get your computer off the ground. A piece of plywood would also be plenty if you're just trying to keep it off of carpet.
IO Crest Black Computer Stand with Caster Wheel (SY-ACC65057) https://www.amazon.ca/dp/B006V9AUMC/ref=cm_sw_r_cp_apa_XI66xbZT7VSKP
This could help you.
Something like this?