Oh yes... XEGS-DS is a full Atari A-bit emulator including the 1088K expansion RAM. It will play thousands of Atari 800 games.
GBAtemp.net - The Independent Video Game Community
wavemotion
NightScript
Ok, so other than the Atari800, what else am I missing here? https://wiki.ds-homebrew.com/ds-index/emulators