One of many hardware projects underway in the land of Acorn, Dominic Beesley’s in-progress CPU Expander sits in the Beeb’s 6502 socket and allows for large local RAM and a potentially faster replacement CPU: 6809/6309 or 65C02/65816. There’s a big FPGA for glue - lots to do to switch just the right accesses to the slow motherboard in time - which can also implement a blitter and a sound chip. And Flex has been seen running!
Video demo here.
See the thread for more, much more:
A blitter for the beeb?