Monkey Magic system could be very interesting. Monkey seems to be one of the rare TV series were the repeated use of magic follows a similar kind of d20 Spell system - Somatic, verbal and material. Also we see him use similar powers.
Couple this high level fantasy kind of image, with the mythical nature of something like crouching tiger, hidden dragon and the Stormridders Trilogy, you could be onto a system and setting that blows the slightly too serious yet loaded with fantasy, Legend of the 5 Rings out of the water.
I still happen to think this is the best suggestion on the board, except maybe for a Carry on style RPG system based on d20 - it would be so original to have a game where rude jokes and sniggering at NPCs statements was rewarded.....
By in the traditional RPG field MONKEY! must surely be ideal. Almost everyone in the UK will know of it and its out on DVD! Not sure about America, but I bet it has a cult following there as well... (and I bet the license is dirt cheap to pick up).