ATX I/O shields for AT boards do exist, I picked up a new one from eBay last year for my SS7 build (item number 154299330683 on eBay UK, still available although a bit pricey). They're just a plain shield with the hole for the keyboard punched out, the neatest solution you're going to find IMO.

Alternatively you could probably 3D print something that would do the job.

...or you can buy cheap blanks and cut the hole for the keyboard, although it's not as easy as it sounds. This is what I did as I couldn't justify the asking price for the ready ones.

ATX I/O shield models for 3D printing

These are already made, at least for AT motherboards in ATX cases.

Cheers everyone.

Wow that is a lot of money for a back plate. Will have to consider my options. May just stick with my PII slot one rig…..

The 3D printed ones work just fine. Just sayin'.

Get a blank i/o and make your own:
https://tinyurl.com/mpr26apb

or

https://tinyurl.com/y6t6hcp4

I went the super-duper cheapskate method instead for my Super Socket 7 build in an ATX case -

No expense or much time taken to solve that problem, which is clearly evident by the super amazing job I did of the cut-out for the keyboard socket. 🤣

In all seriousness, probably best don't do this. But it does work so....

I had a stack of NOS vintage AT backplates from the PPro haul. Most of them were given out to Vogons members years back. For reference, these are what originals look like which have the grounding tabs.

liqmat wrote on 2024-03-05, 16:05:

I had a stack of NOS vintage AT backplates from the PPro haul. Most of them were given out to Vogons members years back. For reference, these are what originals look like which have the grounding tabs.

These are very nice.

I got a few of these some years back, they're basically just blanks with a punched hole of keyboard's DIN connector size.

Another, cheap and a bit ugly option is buying this I/O shield sized 'dust filter' with sticky edges, cutting the desired hole(s) in it and sticking it to the ATX case.