I think the W-3175X release sheds at least some light on Mac Pro pricing. It's better news than I expected about the price of higher-end configurations. Even though it's a $3000 CPU, it's a rationally priced $3000 CPU that is around 50% faster (on applications that use all the cores) than Intel's $2000 CPU. It shows that Intel will be reasonable about Xeon-SP chips in single (and dual???) CPU applications like the Mac Pro - they won't insist on $10,000 pricing outside of 4 and 8 way server platforms.
I've always believed (for reasons outlined earlier) that the Mac Pro will use the big Xeon-SP socket and start with 12 (or so) cores, going up to 28, maybe even to dual-28 in an extreme high end configuration.
I suspect the base machine will be something like:
$6499
12-core Xeon-SP (something like 3.3 gHz base, 4.1 turbo)
48 GB RAM (6x8 - remember SP is 6-channel)
2 TB SSD (they may start at 1 TB, almost certainly not lower - the machine with 1 TB might be $5999 if offered)
Vega 64 or Radeon VII - in a slot, but not standard PC video card form factor)
Options will include:
16-core +$700
22-core +$1500
28-core +$2500-$3000
Possibly dual-22 core (~+$4500) and/or dual-28 core (~+$8000) options - there's no reason to do dual-12 or dual-16 core, because single chips with lots of cores are a better option. All CPUs will be fairly similarly clocked - it's going to be a matter of "choose your core count", similar to the iMac Pro.
RAM available with a significant Apple Tax (but you can also add your own), up to at least 192 GB, probably 384 GB or more.
SSD options
(2 TB +$700 if base is 1 TB)
4 TB +$1500 (from 2 TB)
8 TB +$4000 (from 2 TB)
That would also mean that single-CPU machines (the vast majority of sales) didn't have expensive circuitry to support a second CPU.