Well, there's the SH-5
, but it's archetecture isn't exactly identical to the SH-4
. I'm not sure what all the differences are, but you can see for youself if you look around that website. I believe all the SH series CPUs are downwards compatible with code for written for earlier generations, but I'm not positive you can count on that 100% of the time. Just out of curiosity, why exactly did you want to know about this?