I have 3 diesels:
VW Jetta Wagon TDI - for the wife (& dogs), ~50mpg
Chevy Silverado 2500HD DuraMax - for me (& our horses), ~16mpg (net*)
GMC K5 Jimmy [Detroit Diesel] - for the weekend, ~28mpg (rated, actual unknown)
My DuraMax would do better, except for the DPF that dumps raw fuel into the exhaust for "emissions friendliness." Otherwise,I'd be deep in the 17mpg range.
F the EPA, especially in CA.