Ever tried a gooseneck clamped to you camera and a scrim attached on it?
In the film industry, this was usual as an alternative or complementary to the matte box. BTW a matte box might work for you too, there are a variety of sizes and adaptors for different lenses and situations!
An other way, particularly for optical bench camera's, is a second bellows with two stands (can be found used), mounted on the base rail, in front of the lens. This way you can move these bellows accordingly to the lens movements, that's what Sinar (Norma) propagated at the time.
Linhof has a compendium that can be attached in the accessory shoe. This is the one I have for my Linhof, light, flexible and adaptable.
Below, in the first picture you can see it on the right and in front the filter holder, in the last picture you see the attachment that fits in the accessory shoe (upper left) but here the compendium has been modified a little. How it coms in its simplicity, you can see that in the second picture.