Re: Most email services do not support IPv6
hotmail.com and outlook.com both ping as v4 addresses as you state, but both also redirect me (when put into a browser) to outlook.live.com.
If I ping outlook.live.com I get a v6 address, and not v4 (unless I force v4 of course).
me.com was v4 only thought.
For ref, this is in the UK, on a home Sky broadband.