if you are German maybe you saw the post on Brückenkopf about some cheap toy cars at one of our "1-Euro"-stores (TEDI) . The deal with those was that they have the right scale to be used with 40k or Necromunda! However, while this post appeared I was still in Chile and only now I got the chance to visit one of the TEDI stores... and they still had a few of these construction vehicles. And... look what else I found!
5 of these cars cost only something like 2 Euro! Okay, they are quite crappy in quality but as you can see they match perfect in scale and, very important, they are made of plastic (instead of the metal usually used for toy cars). Therefore, they will be very easy to "modify" and use for Necromunda terrain...