For those who haven't used a 4.7" screen, we have a Moto X we use daily and I'd say its one handed easy/awkwardness isn't significantly different than the iPhone 5/5S (especially if the phones edge is curved). Of course we're all different as is evidence from the 4/5 preference.
You can watch the first video at: http://www.apple.com/live/2014-sept-event/c42d94ee-7dea-40a8-98ba-dbd2da60c965?cid=tw-us-c42d94ee-7dea-40a8-98ba-dbd2da60c965-vi
Looks like Marc Newson just "formalized" his relationship with Apple. Who knows if he worked on whatever gets announced Tuesday, but as wearables are being discussed here posting a video of his previous timepiece designs. http://vimeo.com/48145119
Unless I missed something, except for the mobile app animated gif output, there's no way to embed living images on HC (or nearly everywhere else).
Hopeful the 500px support will lead to greater acceptance, but it's a long road.
It doesn't fit all your criteria, but for some reason I immediately though of the Canon N. Probably the shooters age and strap emphasis. Maybe not best for internal shots though. Could pick up three with your budget.