I'm trying out an ID Slip PE from XP Medical... Theyre pretty thin, but they feel really compact imho. They also don't have elastic around the waist. But because of this, they're reeealy cheap, and comparable to the old tena slip maxi, the previous king of thin and really absorbent diapers. Theyre all white minus a thin wetness indicator that goes down the middle.
Another I would recommend is Bambino's Teddy/Classico/Bianco. They are more expensive than the ID and cheaper than the ABU Simple/Little Pawz/Space. But they have a very similar shell to the ABU line I mentioned, just thinner. Idk the mileage of the ID, but I get a good 5-6 hours of normal use from the Bambinos.