She even has that trusty Dreamcast logo on her underwear!

It's actually not. That's just a generic symbol in JPN (not sure if it's specific to anime/manga or not) to indicate ghost/spirits or anything else that most ethereal in origin. You can see it on or around any chars that are being depicted as ghostly/eerie. The Dreamcast just happned to use a similar logo. (I'm guess they picked it due to the "dream" part of the console's name.)