GURPS is pretty much made to enable crossovers, and Munchkin would fit right into the Narutoverse, if perhaps set on whatever the other continent was from the movie with the Europan-style knights who used "gelel" rather than "chakra." Not seeing any issues there, unless you count a Pyramid subscription. I hear it's big in Wind Country.
--
"Anko, what you do in your free time is your own choice. Use it wisely. And if you do not use it wisely, make sure you thoroughly enjoy whatever unwise thing you are doing." - HymnOfRagnorok as Orochimaru at SpaceBattles
woot Med. Eng., verb, 1st & 3rd pers. prsnt. sg. know, knows
--
"Anko, what you do in your free time is your own choice. Use it wisely. And if you do not use it wisely, make sure you thoroughly enjoy whatever unwise thing you are doing." - HymnOfRagnorok as Orochimaru at SpaceBattles
woot Med. Eng., verb, 1st & 3rd pers. prsnt. sg. know, knows