- 2"2 inch spi display https://www.adafruit.com/products/1480

this is basically a breakout for an spi display, could be driven by https://github.com/notro/fbtft/wiki

- lipo charger like the power-boost: https://www.adafruit.com/product/1903

- breakout for an alps nav-switch http://www.alps.com/prod/info/E/HTML/MultiControl/Switch/SKRH/SKRHAAE010.html

- other (soft) switches for the remaining buttons (what about shoulder buttons?)