Alright... so what if we made it sort of like a "Frank's Adventure" type game.
Only the "city" and "streets" are actually the MS PACman maze.
I find the concept of a "sexy" ms pacman absolutely terrifying... but at the same time... comedy gold. and I think @Peaceblossom who suggested she be a creepy old lady trying to be sexy who looks and sounds like she's been smoking a pack of cigarettes for thirty years is a brilliant idea. She could be seen walking the streets like a hooker, and when you initiate dialogue it could bring up a little portrait window of her "flattering" face complete with too much makeup and wrinkles.
The game itself could be basically a few npc trading sequences intertwined with some exploration of the "overworld" map and several smaller buildings/areas.
The center area where the Ghosts respawn and bounce around could be some sort of nightclub.... where you can hear the bass booming (from some pacman techno remix) from a good distance away, and it gets louder and clearer as you get closer, enter, etc.
...and the final sex scene should just be a ripoff right from the arcade game "intermission" where her and pacman meet.