But it's not an album. It's a song on an album. The length is irrelevant.
This. Had the song been released separately, or the album in parts (with Disc 1 coming out one part of the year, then Disc 2 later on in the year), it might be considered an album (although you'd have people fighting over whether or not an album released in two parts should be considered one album or two - see Ayreon's
The Universal Migrator, Beardfish's
Sleeping In Traffic, Pain of Salvation's
Road Salt, or Justin Timberlake's
The 20/20 Experience).
And I agree - album length is irrelevant. An album's (physical) medium, and therefore length, shouldn't determine whether or not something is simply an EP or an Album, but more so the content itself. Albums in the 70's were only 35-50 minutes because that's how much a single vinyl could hold. Double albums were then only about 70-85 minutes in length, but single CDs these days can hold up to 80 minutes, so a double album in the 70's could be considered a single album today (and vice versa).
Had
Scenes From A Memory been originally released on vinyl, it would have been a double album with Act 1 as the whole first vinyl and Act 2 on the second. But it's not considered a double album because it just happened to fit. If CDs could hold 100 minutes, then
Six Degrees Of Inner Turbulence would have definitely been a single CD album, and there'd be none of this "Disc 1 vs Disc 2" business that fans get their panties in a twist for. Put the album on an iPod and what happens? It's one album. No discs, no vinyl sides, nothing but six songs on one album, just as it should be, especially intended by the band.
Now, there are plenty of single-song works that ARE single albums with no other songs, but that was the intention of the artist. Look at Jethro Tull's
Thick As A Brick, originally intended to be one song on the album, but vinyl had to limit their intention since the 40-minute piece had to be cut in half. Does cutting it in half make fans think it's two songs when it's really one whole piece? Why should the limitations of the medium define the music when the artist themselves explain their intentions?
Echolyn have a song that is just one whole album,
Mei, which is a 50-minute piece with no other divisions on the CD, but had it been released on vinyl or even cassette, it would have to have been split up.
TL;DR - Physical limitations of the medium shouldn't have any implication on the artists' intention and meaning of a piece's status, condition, or structure. If a song was meant to be a song, then it's a song. If an album was meant to be one whole album (and not seen as two or more parts of a whole), then it's one whole album.
-Marc.