Another avenue would be using a secondary esp8266 (connected via tx/rx fast enough?) to increase the video possibilities via a webpage or directly via vga even. (Since it is possible to achieve 160x200 color vga on a 16Mhz arduino uno, it could be possible on an esp, but I am still investigating this angle.)
My personal goal is a homebrew 8 bit computer as much like a C64 as possible, including graphics (offering only the most used C64 graphics modes however) and sound using a couple of esp8266 chips (cheap and fast) and only if not possible using avr chips for parts of the project .
A section on this site would be great for me and others to post about PET based projects based upon esp8266!