Johanna Rubba wrote regarding "Elvis is in Rock 'N Roll Heaven":

> In your last example, the adv. phrase would be a locative expression. I
> don't feel that these are subject complements; I think they modify the
> verb 'is', similar to time adverbials like 'the test is Thursday'.

Johanna:

A locative adverbial like "in Rock 'N Roll Heaven" or a time adverbial like
"Thursday" or "today" can be used in two very different ways, as in the
following sentences :

  1.  The exam was today.
  2.  The exam was easy today.

Only in the second sentence is "today" a verb-phrase modifier--the same role it
has in "I wrote a letter today."  In the first example, however, it has a
different role, one that I would still want to call a "subject complement."  You
and I are stipulating different definitions of that term; I would choose to
define it as something like "the phrase that follows a linking verb and
expresses some equivalency, quality, or attribute of the subject."  In that
sense "today" in sentence 1 "complements" the subject noun phrase "the exam"; in
contrast, "today" in sentence 2 modifies the verb phrase "was easy."

Dick Veit