Emmanuel,

Maybe it's a weird idea, but could we have a MTL-file added in the same way as a texture?

It could work in such a way, that when importing a texture, you are asked whether you want to import an image, or a MTL-file.

Seen the beautiful textures Whippetsleek is making, those could be used directly, without having to use a text editor to change the OBJ and MTL files.

Hans