I've spent long enough trying to work around @unity3d splitting my Blender mesh into submeshes (even though I have no materials, everything shares the same UVs) that maybe I should've just written my own renderer

I'm sure everyone feels this way about their particular situation, but it's wild to me that there's no checkbox when importing to just merge all submeshes it thinks it's found.

If anyone's looking at this thread and not looking at the replies, I did get help from two friendly folks and was reminded that AssetPostprocessor exists -- which is such an essential feature I can't believe I forgot about it!