Given that most schools have classes ranging from 45 minutes to an hour, it is not hard at all to fill up a class with just the bare bones Kukkiwon material. Take up the first fifteen minutes with warming up and you have only a half an hour to forty five minutes. A lot of schools do block teaching, so one night, everyone may be learning blackbelt material, and another night yellow belt material. I find this practice distasteful, but it is fairly common from what I have seen.
Article 10 : Subjects of Promotion Test
1. Test of Techniques
(1) Poomsae (Forms)
(2) Kyorugi (Sparring)
(3) Kyokpa (Power check)
(4) Special technique
Kukkiwon doesn't seem to want to put the minimums anywhere accessible, but from what they put there, it seems to not be that much at all.
Australia's recommended requirements include:
4 Tageuks
Koryo
One steps
Two or three steps
Non-contact sparring
10 SD (surprising number!)
3 breaks
Theory
That doesn't sound like it takes too long either.
I just don't know, we seem to be able to jam a heap of information into each of our classes.