This is what my Astral source told me...
In order to get MHD (Mpix and Mescape titles), you will need to be a sub to the SD Mpix service in some way shape or form.
1) If you are a "Movies Package" sub that includes TMN+Mpix+Supers with either BEV or Rogers (or any service provider that chooses to launch MHD moving forward), you will automatically get MHD at no incremental charge, just like you automatically get TMNHD at no incremental charge.
2) If you subscribe to Mpix as a standalone service from BEV/Rogers (+ others down the road), you will automatically get MHD at no incremental charge.
However, if you only sub to TMN as a standalone and don't sub to Mpix, you won't get MHD, but you will still get TMNHD.