Diy custom T7910 build

Take note that Dell uses intrusion switch on those workstation.  It won't turn on if the switch detects the side panel is opened.  Must depress the switch circuit to closed position.

Power distribution is proprietorship design.  Be mindful it isn't a standard ATX.  DIY is costly at the end.  Reference to user manual for components.

https://www.dell.com/support/manuals/en-us/precision-t7910-workstation/precision_t7910_om_pub/system-board-components?guid=guid-6ee3ff83-7940-43e3-a4a6-be34eecc59cc&lang=en-us

@Chino de Oro​ oh I see! So I need to enable the two switch to power on the motherboard.

Take note that Dell uses intrusion switch on those workstation.  It won't turn on if the switch detects the side panel is opened.  Must depress the switch circuit to closed position.

Power distribution is proprietorship design.  Be mindful it isn't a standard ATX.  DIY is costly at the end.  Reference to user manual for components.

https://www.dell.com/support/manuals/en-us/precision-t7910-workstation/precision_t7910_om_pub/system-board-components?guid=guid-6ee3ff83-7940-43e3-a4a6-be34eecc59cc&lang=en-us

I want to make a pc house like the one in the image, so size isnt a problem. The ATX case was too small for this, and the full tower case was too big in size to my room, so I decided to make the whole case like that to save space, and this way I could even get some good additional cooling for the components

It's probably in the manual, but you're also going to need a power distribution board.  Search "precision 7910 power distribution board" and they're easily found on eBay.

The wall idea is nice, any DIY project has its own unique reasoning.  Just want to point out the power issue.

There are some inlaid computer desk for DIY builder as well.   

Sadly or not, I dont have space for it to be built in my desk. Also I would need a new desk for it. (I have made a custom desk to my room, its about 400mm wide but more than 2meters long. Thats why full towers will not work. ) Its easier just to hang it on the wall. 
So just to make everything clear, I need two switches right? I have found some good deals on Ebay. About the intrusion switch: I did not find a dedicated switch to this exact motherboard, but I found some what looks exactly the same whats in the documantation. 
Here is the two: 

I have another thought contributing to your DIY project, if you do not take advantage of all the flexbay from a T7910, you could get a whole system of T7810 for around $200 USD and stripping it down for your project.  At the least, you will know exactly how each components connected.  Besides the wall mount chassis, all OEM components could be re-arranged and having all needed parts at once.  Fans and lightings can be added at the end.

It could be a more difficulty to source parts than a whole system. 

@Chino de Oro​ That sounds logical, but I really want to keep this in budget. Buying parts what I cant use afterwards, and I only can get money back if I sell it.. too much hassle and its uncertain that I will even be able to sell it. If I cant use a part, it will be just junk (at least to me). Until now all the parts (2 ram, 2 processor, 2 aio, the PSU, the MB, an M.2 ssd adapter , and the two video card) did not cost more than 550 usd, with 20% tax and shipping from US to Hungary. Most of the time it cost more than the part, but it worth it . So its pretty good now. I want to make this project from as little money as possible (without sacrificing quality and the necessary strength of the parts) so I could start my next project right after that. So what I need now is to know what should I buy. Is the two part I attached what I exactly need? 

The front I/O board might be the right part but the intrusion switch is not.  If you can locate the header on motherboard and short the correct pins, you won't need the actual switch.  

I've removed my intrusion switch and disbaled in BIOS on my T7910 with no issues and can remove the side cover and boots ok, but with my new T7920 it's a no go!!