Interestingly enough, we don't have any such documentation. After spending some time combing our knowledge base and talking with some others around the office, I've discovered the official stance from Dev has always been to follow the same migration path for SEPM and clients. This is interesting to me because as a member of our support team, I've always been told and always tell customers it's okay to skip to the latest version on the clients. In the end, it ends up being a matter of Dev sticking to 'letter of the law' and support going with what is easiest (and still works just fine). In practice, I've never heard of or dealt with a situation where clients didn't migrate properly to an MP build directly. I've also seen a number of cases where SEPM databases have been corrupted because the migration path wasn't followed.
So it's an interesting scenario... we have two equally valid stances being thrown around: one because it's the way it was developed (and QA'd) and one that is a shortcut that always works. I guess if it really got ugly we'd have to go with Dev's stance... but until that happens, we (Support) will continue to preach the shortcut.
As for the post about having to go from MR4 > MR5 > RU6a > RU6MP1/2, here's the proof that you can at least skip MR5...
Migrating to Symantec Endpoint Protection 11.0.6005 (RU6a)
http://www.symantec.com/docs/TECH131653
- Note the "Migration Paths" section. It lists all the builds that you can migrate from and all 3 of the MR4 builds are listed.