> BeagleV Ahead Single Board Computer (SBC) (comes w/ mainline Linux support, no Intel/ARM/AMD shit in their cores, uses RISC-V architecture, is completely open source and has touchscreen compatibility)
> an open source USB-based HID-compliant resistive touchscreen (like the ones they use for raspberry pi's, such as the XPT2046 touch controller). Just make sure it's Linux-compliant. Note that the XPT2046 is compatible with BeagleV Ahead, however it requires manual setup.
> a HDMI/USB case for a raspberry pi for the buttons (power on/off and volume up/down + HDMI/USB ports to wire to your board, just make sure the GPO mapping works w/ BeagleV) and a 3D printed plastic display case to house all the components and use like a regular cell phone