At this point in the year I would definately wait for Gemini Lake (Apollo Lake successor) which will come with a proper native HDMI 2.0 port instead of the dreaded third party DisplayPort to HDMI converter chip on Apollo Lake based boards.
Thats what i heard on the other place too.
So most likely I will do this together with maybe adjustments regarding memory, depending on the specific board.
This will also give me time to find a suitable case. Top solution would be a cheap used PC-C37B USB3 where I replace the reset Button with a window. The Milo ML04 might also be suitable and is also still in production. The key thing is a bit ugly.
Beside that I found it really hard to get a relatively clean/nice case with a standard 5,25" bay and possible usage of PCIe slots.