Sticking to HEDT, rather than server components, the 3990X is available, appropriately enough, at $3,990 retail. This is 64 cores.
> 256GB of DDR4 ECC RAM (instead of 4GB) will cost about $1200, not the $1350 spent.
This is not possible as a combination right now. Threadrippers (as is the case for all mainstream and HEDT processors from AMD) can only use unbuffered DIMMs. The largest unbuffered ECC DIMM I have been able to find is 16GB, which maxes out at 128GB with 8 DIMM slots (I haven't seen larger for any TR motherboards).
> For $1440 in storage drives, you're either looking at dual 4TB SSDs if you want SSD speed, or an external 4-bay NAS with 3 8TB drives.
If it's a capacity play, you can easily get more than 3x8TB if you install into the tower directly, rather than a separate NAS. Especially with Threadripper, the motherboards tend to be large and 3rd gen need massive cooling solutions. There should be room for at least 4-8 3.5" drives in the tower.
Still, the modern god box is a good sight better than the old one.