SuperMicro do sell modular power supplies and you can fit their workstation power supplies to some of their server chassis. Depending on the SuperMicro chassis, the power supply may not even have any cables at all, it simply slots in, and is hot swappable, and it is the chassis that has the cabling, and again, some of those are modular. You can also make a modular power supply out of a regular supply, though it is a bit of work obviously. One of my SuperMicro (CSE-846) cases has 1280w PSUs and the other SuperMicro has a 2kW PSU, both are 80+ Platinum.
Not all server chassis obviously, but many have fans mounted at the front and pull air through the case, over the motherboard, through some plastic ducting, and out the back. Some server designs have only a heat sink on the CPU, and rely on this ducted air flow from the case fans to keep everything cool. RAM header orientation will often be due to CPU, VRM and memory controller orientation, but mostly it is about real-estate on the motherboard and physics.
Retail market for server chassis is pretty abysmal. You might consider a Cooler Master, or a SuperMicro or an ASUS case. Depends on your budget and your willingness to use a Dremel.
If you are considering a 2U rack mount case with a full-sized GPU, you might want to look at cases that specifically mount the GPU sideways, there are quite a few out there that will happily take two GPUs, though the cases are often full-depth. Just be aware that server GPUs and consumer grade GPUs have different cooling options and consumer grade cards may not fair well if the case is too close to the exhaust fan.
Instead of a riser, and fighting for a PCIe slot, you might also consider a PCIe extension cable, and then fabricate a custom bracket to hold the GPU in the desired orientation.
Not all server chassis obviously, but many have fans mounted at the front and pull air through the case, over the motherboard, through some plastic ducting, and out the back. Some server designs have only a heat sink on the CPU, and rely on this ducted air flow from the case fans to keep everything cool. RAM header orientation will often be due to CPU, VRM and memory controller orientation, but mostly it is about real-estate on the motherboard and physics.
Retail market for server chassis is pretty abysmal. You might consider a Cooler Master, or a SuperMicro or an ASUS case. Depends on your budget and your willingness to use a Dremel.
If you are considering a 2U rack mount case with a full-sized GPU, you might want to look at cases that specifically mount the GPU sideways, there are quite a few out there that will happily take two GPUs, though the cases are often full-depth. Just be aware that server GPUs and consumer grade GPUs have different cooling options and consumer grade cards may not fair well if the case is too close to the exhaust fan.
Instead of a riser, and fighting for a PCIe slot, you might also consider a PCIe extension cable, and then fabricate a custom bracket to hold the GPU in the desired orientation.