Looking for Add on Expansions slots for a custome case mod

I acquired an OLD ,I'm assuming, IMB case, that doesn’t even have a slot for motherboard inputs. So, as there are no options for me aside from ribbon cables, I'd like to remove some rivets and replace the old backing of the case some sheet metal. This brings me to my point of the post. I'm looking for a screw on or weld on expansion slot with like 4 to 5 slots in it. I've tried looking online but I can only find one from a company that has since gone out of business, and that one is still a 7 slot case design. Any help would be appreciated, perhaps a 3d print would be helpful, but I don’t see that as a huge option for me. Will be posting pics on here once the mod is complete. I was planning this as a sleeper build, re-purposing the turbo button as a fan speed controller.

I've not come along any myself. You might be better off making your own. If you have the tools to remove steel rivets then you could probably cut your own. If you like I could probably find the dimensions for you.
P.s. It's not important but custom doesn't need an e

Thanks, I was afraid of that, I haven't really worked with making my own slots before, but it did come with a removable expansion slots. I could cut that down to 4 slots and I think that will be good enough, I just need to find a way to attach another bracket onto there. I'll see If I can make a cad design or something that would work out better for me.

Well, please correct me of I'm wrong, but what you are aiming for is to make a frame to support pcie expansion cards right? Just like at the back of conventual pc cases. Now what I'm not sure on is, is this going to be cut into the old case or a separate unit that you will have next to it? If it's a separate unit then you can get the extension ribbon cables and have them running into the cage. Is that what you mean?

No the case I'm removing the rivets for the back side( the part that normal has the pci e slots and motherboard i/o slot ) and replaceing it with sheet metal and attatching with rivets again, and cutting out a modern slot for the new mobo ( as the old wont work, there simply isn't a slot for one only the old giant 5 pin circular port is there ) and the new cutout for the pcie expansion slots

The case in question.

The Rear

Inside of the rear

Hope that clears up the confusion

Pcie cards use the same slots as pci cards. You might be better off saving the pci panel and reusing it
Particularly as it is riveted separately.

You're right.Also, I could just cut it down to 4 slots like the and use the 5th retaining bar as a bar to screw or rivet into the bottom. I'm not going to lie, I am incredibly excited about starting this project.

It should be really cool. I love old cases. But I will warm you, the steel can be so sharp. So just be careful, even with the expansion port covers, they are made of rolled steel and then stamped, do the edges can be razor sharp

Thanks I will definitly be careful.

I fortunately found a replacement motherboard tray that I can re-appropriate to fit in this case, I just need to make room for the PSU I selected and I think it should work quite nicely.

If anyone stumbles along this post and is searching for a similar answer. I was looking for a micro atx stencil and I found a forum on the evga website looking for the exact same thing I was so SCORE for me.

This is the one I found:

Search for motherboard trays and you should find something similar.