If you are prepared to put up with less performance, then a diesel should be more economical than a petrol engine. At the workshop, we have a 1.8 petrol engine Nissan 1-ton and a 2.2 diesel Isuzu 1-ton. Both have canopies. The Nissan is astonishingly heavy on petrol, averaging 18l/100km (15 miles per gallon) whereas the Isuzu does 9l/100km (31 mpg). All cars get serviced at 10000km and the Isuzu has not had any problems yet, it has covered 220000km and is 4 years old. Performance wise, both are pretty poky but it is noticeable that the Isuzu is less willing uphill and you have to change down more often. Our previous Isuzu lasted 6 years but unfortunately got stolen. It turned up completely stripped on the side of the road a few weeks later, even the window glass was gone.
We only bought the Nissan as it was very cheap at the time, but it costs more to run. You are right about the clutch though, you need a powerful left leg to push the pedal, even though it is a hydraulic cylinder.