A 3.8 Ghz Pentium 4 and fully DMA-compatible ISA slots seem to be possible now...

http://www.ibase.com.tw/2009/mb865.html
http://www.ibase.com.tw/2009/Manuals/MB86510.pdf

Its a motherboard running an Intel 865G chipset, with the ISA DMA compatible ICH5 southbridge. Its got onboard 100Mb ethernet, two SATA ports, a compactflash slot (That takes up the slave on the secondary IDE channel) An AGP 8x slot, 4 PCI slots, and 2 ISA slots. It supports 800Mhz FSB Pentium 4s in LGA775 sockets and it'll take 2GB of RAM. The only downside is the ZIF-style Floppy connector, that it will only take 1 floppy drive, and that it will not take any flavor of 5.25" floppy drive.

Found one for sale too. No idea on the reputation of the seller and this site, and the nearly $400 price tag doesn't help matters...
http://www.interloper.com/products/product-de … ch#.U2HDdPldV8E