This answer doesn't provide an other way (which would be groundbreaking for the decoration community), but explains the necessary conditions to trigger the behavior as seen in the video. (Read: I researched this a bit and wanted to document my findings.)
As you wrote, this method requires the non-pickable item to be within a (wrappable) container.
Rules
- A house field can normally hold 1000 stacks. (You'll get an error upon trying to move a next item there.)
- More items can be put by for example:
- destroying a container with a melee weapon,
- unwrapping an item,
- being overloaded (red zero capacity) and making action that would make a new item (e.g., using a flask of demonic blood works great),
- throwing over stairs/ladder.
- Overflow logic happens at ~1050 items. All items beyond the 1k limit are "evicted" (probably just like when moving out of a house):
- wrappable items are wrapped,
- pickable items are grouped,
- non-pickable items are discarded,
- non-pickable items within wrappable items use the first condition and land in inbox.
- Unrolled carpet uses a separate slot (is always displayed on top).
Single-floor houses
Since I don't own a multi-story house, I came up with a setup that works for walkable-over items. (So sadly not lockers).
As with the rules above, only stairs can be used to put a non-pickable item as 1001st. However, an occupied bed has a very useful feature: it is not visible on the "browse field" list and doesn't count to the limit, while keeping its position on the list. This is a powerful feature, but with a limitation: only walkable-over items can share a tile with a bed.
Here's a procedure to put an item as 1001st and "evict" it:
- Put a bag and 998 stacks.
- Unwrap a part of a bed (1000th item) and put a char to sleep.
- Place the walkable-over item on top (again visible as 1000th).
- Wake up the char: the item in question is now 1001st.
- Put more items to trigger overflow. A simple strategy is to:
- put a "chest of drawers" kit in the bag and unwrap it (works).
- put a crate and fill the drawers with trash (the crate is at the end)
- destroy the chest using a melee weapon
- the chest is now at the top: repeat the process with chests until overflow triggers.
Summary
Sadly, a non-pickable body or furniture is discarded in the process – it must be contained. There is another use-case for this trick: as items are not "evicted" when transferring a house, this procedure may be used to quickly move your heavy belongings to your inbox.
BTW Yeah, I know that "pickable" refers to "picking", not "picking up"...