I recall reports of Elbox's "Dragon" which ran @266mhz effectively being about the speed of a 40mhz 68040 in real-world tests due to compatibility trapping, etc.
IOW, coldfire ain't gonna happen for the Amiga.
Not at a speed that makes any sense.
Frankly what I'd like to see is something like taking a single-core Atom or Geode and running a virtualized 68k CPU with JIT on it on an Amiga accelerator card. Although I'd wager interfacing a virtual CPU to real hardware in that circumstance would be a nightmare to attempt.
