How to have child/parent relationship between term of one vocab and the term of another vocab?

I am trying to put together an advertisement site for selling vehicles, and would like to use drupal to do it. I have done a bunch of reading in the handbook, but I can't figure this out. I basically have the gallery aspect working with cck, imagefield, imagecache, thickbox, etc and am using a custom content type to create the vehicle listing. However, I want to use taxonomy for flexible arrangement of the vehicles, but am having a problem figuring out how to best do this. I think I need to have a term of one vocab to be related to a term of another vocab, but I don't think this is currently possible. For example - vehicle would be the vocab, it would have terms like car, truck, boat, etc - then makes of vehicles (a different vocab?) like Pontiac, Audi, Chevrolet, Porsche, etc - then models of vehicles (new vocab?) like Grand Am, 911, Grand Prix, Silverado, Corvette, A8, etc, and then possibly model year of the vehicles (new vocab?) like 2006, 2007, etc. These would all go together so that you could search for all cars, and it would list all but the Silverado (truck), or list all the Chevrolets and get the Silverado and the Corvette (both truck and car), or list all the Grand Ams, or list all vehicles that are model year 2005. I would think it be best to have each of these items I have listed as separate vocabularies, but especially the make/model of the vehicle are related. Grand Ams are always made by Pontiac, so I don't want the person creating the content to be able to put the Grand Am in as a Porsche. Any ideas how I would do this? The categories modules? It looks like it is beta at this moment and I couldn't get it do what I thought I wanted on its test site. I have used taxonomy before but only for very simple tagging. Any idea how someone who knows how to use taxonomy would approach this classification issue? I am utterly amazed at how simple it is to create a custom content with drupal - it is really amazing! Thanks in advance!