Ken Fager posted the mod of the week on his Flickr stream with his Nintendo DS running Mac System Software 6.

Ken gave TUAW the gritty details of how he achieved the mod.
"First, grab a DS flash card and install MiniVMacDS onto its root directory.
Once that's done, place the Mac Plus ROM into the "vmac" folder along with a System 6/7 install disk (you can make a blank disk image using Disk Utility).
Finally, turn on the DS and select MiniVMacDS. It will boot the disk images. From there, install (minimal) System 6 onto the blank disk image."
Well played Ken, well played.
Check out the DS keyboard after the jump.