I don't know what the situation is in the US but here in the UK we have Bluray disc recorders with built in Freeview HD channels.
This means its possible to record in HD but only from the channels available via the internal tuner.
It is not possible to record in HD from any external source.
There are only about 6 or 7 Freeview channels in HD but these do include BBC1-4 and C4 and ITV.
Any HD recordings from these channels can be burned to BD-R discs.
ITV and C4 recordings are limited to a once only HD burn but BBC recordings are not currently restricted.
So it does mean its occasionally possible to create a Bluray HD recording of a film not commercially available.
HD recording from an external source would require an HDMI INPUT . I don't know of any recording devices that include one.
My Panasonic Bluray disc recorder also enables recording of HD content to a dvdr but obviously limited by the capacity.
I've not done any of those so I don't know which devices would play it back . I assume a normal dvd player wouldn't