I manage to activate a 3.5" Riverdi touch screen display. This is a cheaper resistive touch screen model with FT800 controller, and capacitive touch screen model with FT801 controller seems that is pin compatible.
Please note that display has to be rotated for 180 degrees since it's going to be mounted vertically not horizontally (as in a handheld device) for optimal viewing angle. On the picture below I just place it over Arduino shield but in practice it need its mounting rail or bezel that has to be fixed on the front panel.
So now we have an upgrade path to more capable display (faster controller, truetype fonts, selection of resistive and capacitive touch screen, built in audio, etc.).