The VOID buggies aren't OOP, they're sold by Scotia Grendel now (unless that's some even older one).
There looks to be quite a nice selection of post-apocalyptic vehicles out there, between the stuff made by Ramshackle Games, West Wind, GW (Orks, but easy to convert), Urban Mammoth/Scotia Grendel, Fenryll, Old Crow/Ainsty and others. Not to mention conversions.