I haven't seen an ISA slot on any DDR boards for any processor. The last ISA slot I saw was on the Iwill KK266 Plus. I have the orignal KK266R, and it is very stable Athlon playform, based on the VIA KT133A chipset. Of course, it only supports SDRAM, though there is an on-board RAID option as well (KK266 plus R)
The last Intel solution with an ISA slot would be the VIA Apollo Pro 133A, in various boards. I don't think any Intel 815 boards have an ISA.
Basically, your best bet is the Iwill KK266 Plus.
Regards,
Craig