I'm looking for a Solitude interior texture, smdbwalint02.

However, it doesn't seem to be in Textures.bsa (I've tried several tools).

In fact, none of the Solitude interiors seem to be there.

Any thoughts?

NifSkope points to three different textures for the parts of smdbwallint02.nif:
textures\architecture\solitude\SstuccoWallInt01.dds
textures\architecture\solitude\SIntWalltop01.dds
textures\architecture\solitude\SIntColoumn01.dds
I can find them all in the extracted textures.bsa

Ah, thanks.

In the CK, editing the model entry for the object shows alternate textures named smdbwalint02:0 etc, but I guess those don't exist.

I'll check whether that mechanism allows me to override SstuccoWallInt01.dds with a different texture.

In the CK, smdbwalint02:0 and so on refer to the NiTriShapes in an object's .nif. Basically, a specific mesh that an object has. Some objects, like that wall, are just divided into more than one mesh for ease of use. Each mesh is then just linked to a texture, via the BSShader, but you probably already knew that. >.>

Again, thanks - I tried Nifskope, and was pleased to find that it's easy to identify and change the textures used on each part of the model.

However, since I've been using Texture Sets in the CK so far, I decided to stick with that approach, rather than make a new model.

Hopefully, that doesn't cause a performance problem?

It shouldn't. You may get the occasional texture swap warning message, but that should be it.