www.sinkpositive.com have interesting gizmo which reduces significant amount of water.
It allows washing hands and than using gray water for flushing the toilet.
It is a copycat from Japanese bathrooms.
How difficult is to keep cleanliness if the toilet , and how problematic is the condition of the seat for people ?
Do they complain a lot , do they try to stand up on the seat the way is sometimes practiced in the east ?
What about using temporary paper covers for the seat , how acceptable is that ?
One of the possibility is the self cleaning toilet seat, but it would be expensive proposition.
But what about having multiple precleaned toilet seats
stored on the shelf which could be placed and removed by the user ?
Of course latching mechanism got to be very simple.