You can consider looking for IDs that are design and build, they would have more expertise in building high functional carpentry with good safety requirements.
I did a quick search above on "kids rooms" and there seem to be some photos with bunk beds too
https://www.hometrust.sg/photos/s/queenstown-dawson-place-dawson-road-hdb/7980/modern-kids-room-with-platform-bed-and-built-in-bed
https://www.hometrust.sg/photos/s/804b-keat-hong-close/54319/scandinavian-kids-room-with-bookshelf-and-downlights
https://www.hometrust.sg/photos/s/100-kim-seng-road-singapore/51113/contemporary-kids-room-with-bookshelf-and-children-s-beds