MiSTer FPGA Forum

I can get a nice platform floor style usb controller for it and think it would make a cool gift for her.

DDR is based off of Playstation hardware so not until there is a Playstation core. But that being said while it is at the limits of this hardware it may just be possible and there are people working on getting Playstation support. Also just because Playstation support is added it doesn't mean the arcade variants will be added. But no one knows at this point what people will do. I would say though at least this is a year off so probably not a christmass present for this year. If you like Turbografx-16, genesis, snes, nes, GBA, neo geo or classic computer or arcade games then it is great now. There are still quite a bit of cores in progress.

If you are looking for a Dance Dance Revolution project you could go with modding an original Xbox. There are a few DDR games that run natively but there is also Stepmania. With Stepmania you can have songs from the original arcade releases or tons of other releases. Playstation 1 emulators are also a thing on original Xbox, but I can't say how well DDR would run on those.

Second OG Xbox and DDR! It's a fantastic system for the series and there are tons of options for making pads.

Stepmania is miles above what you could do with a DDR Core, I suggest you check it out! It's already easily available, free, and support custom songs from the community.