Sega Genesis/Mega Drive complete with a working original Sega-CD attachment and original copies of Sega-CD games.
I'm sure no emulator is going to replicate all the quirks of the original, mechanical workings of the CD hardware.
This really is something I'd love to experience in its true, original form.
The way that looped background game music works, for example. The music being PCM CD-Audio, but then having to switch to a short filler-loop synthesized by the Genesis/MegaDrive's original internal sound chip, while the CD mechanism has to seek back to the beginning of the CD-Audio track to start playing it from the beginning again. At least, since I never experienced the Sega CD, I am assuming that this is how it works.
Unfortunately these things are very expensive, so it's still just a small dream of mine.