How is the PCI video card connected? What kind of sorcery (riser) is this?
This was actually an unexpected turn of events 😀 The video card is a regular AGP GF2 MX, and initially I intended to just use a normal "right-angle" AGP riser for it (so it would occupy the same position the green PCI audio card now uses) and deal with the audio later. But this AGP riser I found really cheap turned out to be a "left-angle" thing I never knew existed - the board even refused to start with the GF2 in its "normal" position (away from CPU and its heatsink facing the mobo).
I thought this was a disaster (because AGP risers are hard to come by these days and are often pricey) and that the build came to a full stop for indeterminable period. But then I decided that a slightly mangled case that works is better than pristine one that doesn't 😀 So I bought a file and took it to the rear of the box - to remove the metal preventing VGA port from being connectable.
The rest of the cards are connected via totally regular PCI risers which are still being made today (just PCB extending the slots): the audio card is on the "2-storey" one, and the NIC is on the "1-storey" riser.