> Recently, they are sold as complete systems.

Complete Sam4x0 systems have been sold since the beginning 7 years ago.

> MorphOS is supporting it with future release of MorphOS update. They will
> only support one or perhaps two SAM.

Yes, only Sam460.

> They have
> SAM 440
> SAM 460
> SAM 460 EX
> SAM 460 CR

That's a little confusing. It's more like this:

Sam440
-- Sam440ep
-- Sam440ep-flex
Sam460
-- Sam460ex (incl. Lite version)
-- Sam460cr

> MorphOS contains backwards compatibility with classic Amiga.

...for OS-friendly software, that is. This excludes most old games, which have to be run via UAE.