> Nit: It's the Pi 500+

I really want to hope the name is a nod to the Amiga 500+ (which had twice the RAM of the A500 ..)

This made me do some research and I'd say it appears so.

https://www.raspberrypi.com/news/raspberry-pi-500-and-raspbe...

> Our experiences with that programme informed the development of Raspberry Pi 400, our all-in-one PC, whose form factor (and name) harks back to the great 8-bit and 16-bit computers – the BBC Micro, Sinclair Spectrum, and Commodore Amiga – of the 1980s and 1990s.

(emphasis mine)

So the 400 name is explicitly inspired by such systems, their next one is called the 500, and the upgrade to that is called the 500+. I'd say it's a pretty safe bet that's exactly the inspiration.