Just another idea - have you looked at 4x5 lens-on-a-cone type models? They are solid, compact, and are designed with handles etc.
Cambo Wide, Sinar Handy, GranView, or one of the many Chinese variants (Dayi etc.).
AFAIK all should have a standard 4x5 Graflok back fitting.
Focusing would be by scale focus, if you are not shooting in a manner amenable to ground glass focusing.