[herio]

I don't think you will see new custom chips made to match those chips, however they are small enough to be easy to implement in a modern CPLD/FPGA.

I know of three such projects at the moment:

J-CIA: https://1nt3r.net/j-cia/

FBI: https://www.forum64.de/index.php?thread/84273-wip-fbi-als-er...

VHDL6526: https://github.com/bwack/VHDL6526

The 6526 CIA from the C64/128 is almost identical to the 8520 from the Amiga, the only difference is in the time-of-day clock registers. The 6526 uses BCD encoded TOD, the Amiga 8520 counts seconds since midnight.