I would have thought that it takes too many clicks before the user could see any pictures of the vehicles. The brand names and model numbers are fine for dedicated bikers, but the beginners really would want to relate with images.
With my design, before I had to insert the intermediary pages, it only took two clicks to see the picture of a vehicle (or one click if you clicked on one of the three most recently added vehicles, listed under each category on the home page).
However, I see your point about "beginner" users so I added a thumbnail toggle to the browse page.
I appreciate feedback like this -- what about starting a new forum specifically dedicated to announcing and soliciting feedback on new/redesigned OpenACS sites. This could be a valuable thing, especially for the small or independent developers.