Where to go after Arduino? I apologise in advance if this question is not right for this Stack or if it has been answered before but here goes. I have been learning C/C++ using the Arduino Uno and have gotten the hang of it now (I have knowledge of other programming languages so it wasn't too difficult to get in the rhythm). I was wondering how I would go about creating a standalone solution if I wanted to display information on four or five displays similar to These. I would pull data from a network to display on them too so I would also need to accommodate an ethernet or WiFi shield.
I appreciate any help or pointers in the right direction that can get me started on my journey to creating some custom embedded systems (if that is indeed what I am describing).
There are a lot of much more powerful boards available (especially if you move from ATmega to ARM).  I'm partial to the Teensy boards myself but Adafruit also makes some nice ARM-based boards.  For example, I'm currently developing a multi-user, Arduino-compatible Unix-ish OS on one of the latter (48MHz ARM, 256kB flash, 32kB SRAM) and it runs great.  Honestly, controlling 5 non-graphical LCDs over I²C is should be easily doable on an Uno but if you need more power there are lots of options available.
(No affiliation to either of those companies)