I was just able to preorder this case with the PCIe 3.0 riser at Newegg with a release date of 4-20-21. The PCIe 4.0 version still said sold out.
https://www.newegg.com/black-ssupd-meshlicious-mini-itx/p/2AM-030R-00001
Seconds after I preordered it went back to "sold out" again.