Reddit mentions of 192w AC-DC Power Adapter, 12v 16A

First I think it's a waste of an NES, but only if you are destroying the electronics (assuming they are not already dead). I hope you'll keep the electronics or give them away to someone so that the actual system won't be dead. Maybe your next project could be building a custom NES.

Anyways, I think I know some parts that might help you.

First, A slim 7750

For something like this you should also want a pci-e riser cable/ribbon/kajigger.

Here's another thing you'll definitely want/need for a build of this size. The largest pico psu I can find and an appropriate power brick/adapter to go with it.

However, if you are going to use this for old NES games and such, you won't need the graphics card. The onboard graphics will be more than enough.

There is a significant issue though The pico psu is meant only to run at 160 watts, 200 peak. I pretty sure that pcpartpicker.com is going to estimate power usage to be at max, but the issue is that at max, this system draws 163 watts. Now, I don't know if this would be sustained for long periods of time if you ran the system under full load, but I feel like it would be an issue.

When I say this system, I am referring to this. The psu is not on pcpart picker so it isn't on that, but you can imagine it being there.

You need a PicoPSU like this and an external power supply like this.

You get different power ratings, I just linked to the 80W versions.

[Edit] Sorry, links don't appear to work, but if you search on the Mini-itx.com store you can find them.

[Edit-2] Changed links to amazon links, slightly different products but they do the same job.

[Edit-3] Looks like it comes with the PSU, so you only need the external power brick.

For power efficiency and a media center, but without gaming, I'd recommend an AMD A6 series.

Since you're leaving it on 24/7, I'd also recommend you go with a more custom solution for the power supply. By using a 6A DC power brick along with a picoPSU 24-pin, you can save about 20W. With US energy prices, that's about $20 a year. If you want some extra headroom for power, you could go with this model DC adapter that's compatible in order to get the full 150W from the power adapter.

I'm building a SteamOS box soon that will also run XBMC, and I like the clean lines of the Fractal Design Node 605, although you may find it is a bit bulky and pricey.

Yup :(

Cpu will be g4560

This will be a dedicated rocket league gaming pc, on account that it's the only game i play.

I'll be building the case myself. I'm trying to build it as absolutely as small as possible, like, if the gpu has to lay on top of the cpu cooler, so be it.

I'm banking on the 1050ti, 1050, or possibly the 1030 and and the g4560 to be so thermal efficient that the ,very, lack of airflow won't be an issue.

I'll be using this psu and this ac-dc power inverter.

I've been contemplating the gt 1030 as there is a single slot version, but think I'll end up going for the 1050ti for the power

this power supply is a 9V supply. you still need a 12V supply, rated at 12A. something like this is what you'll want.