Brigade Games UK are my 'go-to' provider of trucks and non-mil vehicles for Ogre Miniatures projects.
British - Atlas grav truck (I have 'black-skirted' this as a hovertruck):
http://www.brigademodels.co.uk/6mmSF...SF300-109.html
German - Thrall hovertruck (but can also be used as road trucks too):
http://www.brigademodels.co.uk/6mmSF...F300-310a.html
EuroFed - Lievre Pick-Up Truck:
http://www.brigademodels.co.uk/6mmSF...SF300-412.html
South Africa - Hippo Heavy Truck flatbed (office and bowser bodies too):
http://www.brigademodels.co.uk/6mmSF/SAC/SF300-608.html
Neo-Soviet - Polevka Lt Truck:
http://www.brigademodels.co.uk/6mmSF...F300-1210.html
Polish - Suwalska Half-Track Ambulance:
http://www.brigademodels.co.uk/6mmSF...300-1303i.html
Indonesia - Kijang Armoured Grav Truck:
http://www.brigademodels.co.uk/6mmSF...F300-1408.html
Mercs - Magnus APC (for a hovertruck):
http://www.brigademodels.co.uk/6mmSF...F300-1503.html
And the Mercs Wizard Jeep (for a hovercar!):
http://www.brigademodels.co.uk/6mmSF...F300-1507.html
A nice mix-and-match provides a wide variety of logistics vehicles.