Placeholder for rob's answer, if he ever gets around to it. Rob, drop me a comment when you post your own version.
Adek Industrial makes ATX mobos with ISA slots. Looks like they only offer one model per CPU/memory generation. Here's the MB-P4BWA Industrial ATX Motherboard for Intel® LGA775 Core 2 Quad/Duo Processors.
- Supports Intel Core 2 Quad, Core 2 Duo & Pentium D LGA775 processors 533/800/1066 FSB
- 4 x 240-pin DDR2 533/667/800 MHz RAM up to 8 GB
- Intel Q965 & ICH8DO chipset
- Built-in Intel Extreme GMA 3000 video (up to 256 MB shared RAM)
- 6 X SATA II interface with 300 MB/s transfer rate
- Supports RAID 0, 1, 5, 10
- 2 x Intel 82573L Gigabit Ethernet & Realtek ALC888 high defination audio
- 1 x PCI-Express X16, 1 x PCI-Express X4, 1 x mini-PCI, 4 x PCI & 2-ISA
- 4 x USB 2.0 ports
Other models are available. Contact them for a quote.
As to DOS workability, my best guess is "uh..... try it and see". Since these mobos are designed for newer CPUs, faster (and more) memory, modern USB, etc... it might "just work", minus newer fancy features like USB, and it might not be remotely bootable. I'd love to try it though.