Legend of the Five Rings 4th ed.
I've seen people have issue with the Kaiu Engineer when they can't sit still for a month to do smithing and engineering stuff; their school skills and techniques almost entirely revolve around it. On The Wall, though? Perfect choice.
If everyone is willing to stick to Duty and Loyalty like glue, Scorpion work well for single-clan adventure - everyone is in on the scheming, while the schools both support each others' antics and generally work better with more. Two Shosuro Actors are better than one.
Any single clan would be interesting. Just need to avoid concept creep from most PCs 'accidentally' being out-of-clan characters.