Hey Gilgamesh
A few weeks ago i published a german guide for portable 4x5 camera and lenses. One of the key features of the guide is a market overview with volume and weight.
Maybe you will find some new companies you are not familar with.
Let me give you a short translation for the tables:
Lenses (columns from left to right)
http://pascalstingl.ch/?page_id=3636#5manufacture, model, focal length (mm), max. aperture, image circle @f22,
image circle divided by weight, 24 mm equivalent, min. aperture, shutter size, weight (gram), filter tread
Cameras (columns from left to right)
http://pascalstingl.ch/?page_id=3636#3Name (
green cameras got a volume lower than 4 liter), manufacture, min. extension, max. extension, weight (gram), length (cm), width (cm), height (cm), volume (liter), Name (
green cameras got a weight below 1750 gram)
Maybe that helps you a bit. I purchased recently a Toyo Field CF and I'm very happy with the decision. Don't fear the plastic body, it is real well made.
Regards
Pascal