Interesting Hiding Spots for the Rod pieces

[Kotenkiri]

Working on a campaign where my party are searching for different parts of the Rod of Seven Parts as other groups are searching for them as well.
It's set in Eberron as i like the magitek aspect.They haven't pick their characters yet.

I have a loose idea of the first 2 pieces are hidden seperately in different locations.
3rd-4th are with one group of lawful Devas or similar. 5th and 6th are with a group of demons.

7th pieces becomes a mad rush to get advantage over the others.

Trying to come up with interesting location to have the pieces. SO far, have stored in Kundarakhold Bank Vault, within the brain of a white or silver dragon (not physically but rather its the portal to the piece) but drawing blanks on possible other locations.

[Xetheral]

For a whimsical campaign I'd suggest the following options:

Buried in a chest below the bottom-most chest in a stack of buried chests. In a time-lock vault that, on any given day, will only open two days before tomorrow. The place after the last place the party looks. In a box third in a row of sequentially numbered boxes corresponding to all of the real numbers. On a doily in the exact center of the empty set.

[Ganymede]

One piece is in the Far Realm, and the only entity that knows its location is a person that had been absorbed by a Gibbering Mouther.