I've been giving it some thought.
Everyone seems to love the idea of building a character with some kind of mutagenic energy, but the characters need to be stripped of their convoluted stats and numerous fiddly skills that take ages to work out...conversely, they could do with some hooks that immediately draw them into some kind of narrative.
I'm thinking of using FUBAR for the basic game structure, then applying some kind of mutagenic point system to buy special abilities and edges, then 6 simple questions.
1. What brought you here? What keeps you here?
2. What is your favourite part of the city?
3. Why do you hide from the mundane world?
4. Why are you still attracted to the mundane world?
5. What do you think of your animal nature?
6. What do you seek in life?
Then maybe a couple of things to tie the characters together, and a way to generate up a city for adventures to unfold in.
There might be something in this...