Simon,
I disagree with this:
"I sincerely doubt we will ever have the option for a 4tb internal drive, for many reasons...."
"Ever" is very slippery word.

24 bit Audiophile anyone?

I hope that mr.G. sees this issue more openly.

External cases are dirt cheap. If I had a say beyond forum I would encourage to offer UltraPack and Audiophile on a customer choice of HD.

a) Outgoing, but cheap external spinner or
b)SSD shipped in external "usb" case, for those who do not want to tinker with stuff, but still want a fast / reusable HD.

With upgrades, I would offer an option of just new content on Flash drive. I believe, even Audiophile does not add more than 256G yearly, so I would offer exactly that, a 256GB (Usb3.1) flash drive with just new yearly content...

Yes, price point will change "somewhat" for those who would want SSD, but folks (and I am sure quite a few users) will see it as investment.

P.S. I think a 2TB SSD should be "enough" for next few years (until 4tb becomes more affordable), unless 24bit is coming soon smile