This is a discussion we've had on previous occasions, and I agree that a 3" record with as many tracks as this could fit the definitions of an album. There have also been instances of an "album" being split into two, or even three or four 3" discs, thus gaining an album's length of music or even more. However, since the CD singles category is the only place where one can enter 3-inches, this is where these would have to go.
But hey, wait a minute, there is something here which defies my sense of logic. Why then, should vinyl singles be defined by their format, but CD singles by their length or number of tracks? Shouldn't this random example from 45cat also be defined as an album using the same criteria? Furthermore, the Petitgand entry is part of a series (Cinéma Pour L'Oreille), where some of the records may contain only one track, while other has several short tracks. What could be gained by putting 2 CDs in the same series in two different categories?
My suggestion would be to leave the 3" singles where they are and adjust the option of adding more tracks than eight.
These are the types of items that do dance around the head of a pin, in terms of definitions.
...I actually agree with all stated examples being albums, on account of the discs presenting a selection of different tracks, not highlighting a single track, with other tracks (or versions of) supporting it.
The fact that these are short compositions means they can physically fit on a 3" CD, but add a few seconds per track (fade outs etc.) and even you would agree by one definition (time) that it is an album.
The format alone cannot be the determining factor in these cases, they are A) convenience (We can fit it on a smaller disc), and B) it's a quirky marketing tool.
I think the other common feature of the examples given, is that they are relatively modern phenomenon...
3" CDs were designed for singles usage, these artists have simply used the format itself as a medium, or feature of their art: "What if I put a whole album on a disc designed for a single?" - "Can I squeeze an album's worth of material on such a disc?"... it's a challenge they may set themselves too, I think.
I will raise this in Mod world, to see if we can have this format (versions of) in CD albums, so they can have an appropriate home there, as this is clearly not an isolated case.
(Possibly more in the database too)
((I'll also continue my quest to have Club Edition as CD album format, alongside Maxi-CD for singles while I'm at it :))