That would be neat, and would come out somewhere similar to a Pi 4 (which are pretty awesome). Note that the Pi 4 has ARM processor cores, but ARM doesn't make

That would be neat, and would come out somewhere similar to a Pi 4 (which are pretty awesome). Note that the Pi 4 has ARM processor cores, but ARM doesn't make either the processor chip or the board. Broadcom design and make the BCM2711 SoC, and the Raspberry Pi Foundation designed and manufactures the board. No doubt SiFive would be very happy to work with someone who wanted to make retail SoCs and/or SBCs using the U84, but as with ARM it's not really their business model to do that themselves. SiFive has made several low-volume chips and boards for potential core IP customers to use for evaluation and development e.g. the $999 HiFive Unleashed. ARM similarly offers a $10000 dev board for the A72.