Well GPF did port DosBox to the DS which plays DOS games.It is an actual CPU emulator, which emulates the x86 and sound. However the port proved too much for the little DS I guess, because he abandoned it.
I played through the first level of loderunner, without a fire button, at something like 1 fps. The compatibility seemed to be there though.
Some people have mentioned an IBM XT 286 emulator would probably be playable. I don't know much about it, but it would probably need to be built from scratch, or a port of something like PicoXT, XT-CE, or PocketDOS.