Do you know of any microcontrollers with a development PCB that exposes > 62 GPIOs if I wanted to wire all the switches directly?
The alternative that I would suggest you consider is I/O expander chips so you can use any mcu with a handful of pins. MCP23 seems popular, see e.g. https://www.abelectronics.co.uk/p/54/io-pi-plus
https://eu.mouser.com/Semiconductors/Interface-ICs/Interface...