Update: I now use a Vufine as the Display. I had to made changes to the boot.txt config-file of the Raspberry Pi: I did set HDMI hotplugging to on and used a 720P HDMI mode as output.
In landscape view mode I can see the full desktop on the Vufine. The Vufine display is sharp and the colors are looking good.
I use a Raspberry Pi 3 powered by a power bank with two USB connectors. So I can plug in the RPi and the Vufine there. The power bank can output 2.4 A.
As the input device I use a mini wireless keyboard with touch pad and some joypad like buttons.
This is a work in progress. I will update the project as time goes on.
Raspberry Pi 3
has build in WIFI and bluetooth
Raspberry Pi case
any case will do it
Rii wireless keyboard RT-MWK08(i8+)
use the wireless keyboard + touchpad of your choice
Ravpower PB-19 power bank
has one 2.4 A and one 2.1 A output port. Use the 2.4 A port for the Raspberry PI and the 2.1 A output for the viewfinder.
The Vufine + display plugs into the HDMI out of the Raspberry Pi. The picture is sharp. So this was a good upgrade.
I use a Ravpower power bank. It has a power LED display on it, so it is easy to see when it is time to charge! The power bank has one 2.4 A output for the Raspberry Pi and one 2.1 A output for the viewfinder.
I use Calibre for E-Book reading. I did install gcc/clang compilers, KDevelop, VLC video viewer, open office and others.