Well, there could be a possibility to *cough* see Geno in the new Mario in Itadaki Street, which mixes Dragon Quest with Mario characters. For those who doesn't know, it's a Square-Enix'd Monopoly game based on many locations of the games featured in. It started as a Final Fantasy spinoff for SNES, and after the Square-Enix foundation, they started to mix characters from both FF and DQ.
In many ways, Geno is the Nintendo's Alucard: A character with a single appareance, an enigmatic background and a huge fanbase (in both USA and Japan). But, unlike Alucard, Geno hasn't appeared again.