clock streching
Considering your last post, I don't understand your initial question. You have defined a special meaning of clock stretching related to your application, independant of existing or non-existing general use of the term. That's O.K., but what your actually asking for?
Regarding ARM technlogy, I noted, that some original ARM datsheets mention the possibility of stretching the input CLK in high or low state, which is just another word for a completely statical clock. I didn't see this kind of clock manipulation mentioned related to memory interface operation and I doubt, if it's of any use in typical ARM applications. It seems to me that HREADY usage is suggested to stretch memory cycles rather than stretching a clock.
As a basic problem, many ARM variants don't provide a READY control of external memory interface. But I don't think that clock manipulation is an appropriate replacement.