This is all terrific, PizzaRollsRoyce, I’ll keep an eye on your progress – you have been bookmarked!
I’m particularly keen to see what you come up with on the Raspberry Pi side of your work. Have you seen what the Atari hackers have been up to with their modern implimentation of DPC+ ? They’re using ARM processors within their homebrew 2600 carts. I’m not sure if it’s anything similar to what you are doing with the VB, but thought it may interest you. Here’s a link: