Engine Capabilities

[Doiphin]

Can you import textures/objects from the Penumbra series? It's a bit farfetched, but it'd be awesome.

Amnesia uses the same base engine as Penumbra last I checked. Despite sounding a little far fetched, I think something like this is actually highly possible to implement if the developers want to.
If this was the case I feel it would be beneficial that in order to have access to the assets, you will need to both own and have Penumbra installed on the computer that is running the editor. This goes the same when playing a level that was created by someone that used assets from Penumbra in Amnesia.