ColdFire is still around but is also not fully binary compatible with 68k. There have been attempts at making Amiga accelerator cards using Coldfires, but I don't think I've ever seen one that was fully finished.

It's not fully binary compatible but pretty damn close. People working on the Firebee were able to make it run pretty smooth, there's some things you can do to trap the old instructions and rewrite. It's never going to work for games and the like, but games and the like from that era have all sorts of other video hardware specific dependencies that are even more difficult to satisfy.

It really is "spiritually" a 68k series processor, just with some cleaning up. I like it.

I am really not an expert in 68k but the Coldfire does not appear to be fully compatible with the old 68ks used in old Macs and Amigas, and Googling around it doesn't appear to have had much uptake if any. It's not being made anymore either.

Coldfires are definitely still in production.

FireBee (http://firebee.org), which is a modern clone of Atari ST, uses it.

No new Coldfire processors made in years, unfortunately. Freescale/NXP seems to be just leaving it.

I guess everyone is just using ARM now.