Perhaps you could find a Pentium laptop with a broken screen, and take apart the insides and adapt something together if the motherboard is shaped the right way.
I believe Pentium predates Mini-ITX.

I have such a machine, the Unisys CWD-5001 (like this: https://www.ebay.ca/itm/Unisys-Cwd5001-ZA-min … PC/250552596524).

It's a great machine. I upgraded the CPU in mine to a Pentium 200.

- Alex

ajacocks wrote on 2020-08-26, 23:44:

I have such a machine, the Unisys CWD-5001 (like this: https://www.ebay.ca/itm/Unisys-Cwd5001-ZA-min … PC/250552596524).

It's a great machine. I upgraded the CPU in mine to a Pentium 200.

- Alex

This is pretty cool. I was hoping to go the custom build route with this though if possible. I really wanted to get a modern mini-ITX case to put it all in.

I don't think you will find smaller than baby AT or micro ATX for socket 7.

If you want smaller and are flexible, VIA made some nano ITX boards with C6 CPUs, starting at around 500 MHz. The cheapest on eBay right now are 667 MHz, but there is a 533 MHz Eden board that's not very expensive (I have a few of those boards waiting to be tested, from 533 MHz up to 1 GHz).

There are industrial application 486s in PC/104 format. Much smaller than mini-itx but pretty limited in expansion expansion options. You would also probably have to design your own case.

debs3759 wrote on 2020-08-27, 00:04:

I don't think you will find smaller than baby AT or micro ATX for socket 7.

If you want smaller and are flexible, VIA made some nano ITX boards with C6 CPUs, starting at around 500 MHz. The cheapest on eBay right now are 667 MHz, but there is a 533 MHz Eden board that's not very expensive (I have a few of those boards waiting to be tested, from 533 MHz up to 1 GHz).

This was what I was leaning toward if the Socket 7 plan didnt work out. So these are totally x86 compatible? Those sound like they will be way fast for most DOS games though wouldnt they?

solidus wrote on 2020-08-27, 00:14:

debs3759 wrote on 2020-08-27, 00:04:

I don't think you will find smaller than baby AT or micro ATX for socket 7.

If you want smaller and are flexible, VIA made some nano ITX boards with C6 CPUs, starting at around 500 MHz. The cheapest on eBay right now are 667 MHz, but there is a 533 MHz Eden board that's not very expensive (I have a few of those boards waiting to be tested, from 533 MHz up to 1 GHz).

This was what I was leaning toward if the Socket 7 plan didnt work out. So these are totally x86 compatible? Those sound like they will be way fast for most DOS games though wouldnt they?

They will be fast, yes, but I understand there is software to throttle faster CPUs for games and other software that runs too fast. They are x86 CPUs, C6 CPUs in the PGA format run on socket 370. The only issue with Epia boards is that they can't be upgraded by a home user, as they have BGA CPUs.

solidus wrote on 2020-08-27, 00:14:

This was what I was leaning toward if the Socket 7 plan didnt work out. So these are totally x86 compatible? Those sound like they will be way fast for most DOS games though wouldnt they?

well it is a x86 CPU ^^

there's also an ITX board with a Cyrix Media GX MMX processor around... other than that that leaves mostly just industrial and embedded solutions but that's a whole different rabbit hole to go down and as said with limited options and usually expensive.

either a via ITX board or a thin client might be an option.

imi wrote on 2020-08-27, 00:27:

either a via ITX board or a thin client might be an option.

I have a thin client with a Transmeta CPU in it somewhere in one of my crates. Really must get round to testing it at some point. Smaller than a laptop 😀

Doesn't quite fit your requirements OP, but I've always wanted to play with one of these:

Meant for industrial applications. PCI & ISA slots, and ports for days. You'd probably want to run Win9x or FreeDOS to get the most out of it.

imi wrote on 2020-08-27, 00:27:

well it is a x86 CPU ^^ […]
Show full quote

solidus wrote on 2020-08-27, 00:14:

This was what I was leaning toward if the Socket 7 plan didnt work out. So these are totally x86 compatible? Those sound like they will be way fast for most DOS games though wouldnt they?

well it is a x86 CPU ^^

there's also an ITX board with a Cyrix Media GX MMX processor around... other than that that leaves mostly just industrial and embedded solutions but that's a whole different rabbit hole to go down and as said with limited options and usually expensive.

either a via ITX board or a thin client might be an option.

Ok makes sense. Since the Mini-ITX form factor was introduced around 2001.. does that mean the Pentium 4 is likely the earliest Intel CPU that had Mini-ITX mobos socketed for it? Or were there mobo manufacturers that created boards that were socketed for older CPUs? Im not totally clear on how soon after VIA introduced the form factor that 3rd parties began making boards using it. Seems like VIA originally just created this for their own CPUs of course

Pierre32 wrote on 2020-08-27, 00:38:

Doesn't quite fit your requirements OP, but I've always wanted to play with one of these:

industrial DOS PC.PNG

Meant for industrial applications. PCI & ISA slots, and ports for days. You'd probably want to run Win9x or FreeDOS to get the most out of it.

Thats actually really cool. I am fascinated by small form factor. I can always jam a bunch of cool stuff into a full tower... but small form is just so cool

ajacocks wrote on 2020-08-26, 23:44:

I have such a machine, the Unisys CWD-5001 (like this: https://www.ebay.ca/itm/Unisys-Cwd5001-ZA-min … PC/250552596524).

It's a great machine. I upgraded the CPU in mine to a Pentium 200.

- Alex

I also have a CWD-5001 and it is the smallest true Pentium original build any one will ever find. Great little machines ! Also upgraded to Pentium 200-S, 32Mb EDO plus Adaptec 2940 and use an external SCSI CDrom with it.
Added: it is 11.5" wide x 9" deep x 3" tall.

Here is a previous topic talking about small form factor Socket 7's: Smallest Socket 7 Motherboard

Horun wrote on 2020-08-27, 00:55:

I also have a CWD-5001 and it is the smallest true Pentium original build any one will ever find. Great little machines ! Also […]
Show full quote

ajacocks wrote on 2020-08-26, 23:44:

I have such a machine, the Unisys CWD-5001 (like this: https://www.ebay.ca/itm/Unisys-Cwd5001-ZA-min … PC/250552596524).

It's a great machine. I upgraded the CPU in mine to a Pentium 200.

- Alex

I also have a CWD-5001 and it is the smallest true Pentium original build any one will ever find. Great little machines ! Also upgraded to Pentium 200-S, 32Mb EDO plus Adaptec 2940 and use an external SCSI CDrom with it.
Added: it is 11.5" wide x 9" deep x 3" tall.

Here is a previous topic talking about small form factor Socket 7's: Smallest Socket 7 Motherboard

Ah that thread is perfect.. time to read!