Beyond The Exterior
...and so on...
We've now finished the exterior to an extent that it can pass for complete. Sure, one could look around for more exterior trim to model, especially on more flamboyant cars like the 1950's models. The Bel Air in particular had many different styles and configurations. You should by now have a very good command of how anything else related to trim modeling would be done.
The main techniques I keep returning to always deal with spline projection, or creating new geometry from existing points and polygons. This can get you through 90% of anything else on the car you can think of. In fact, I wouldn't be surprised if several of the readers doing this tutorial haven't pioneered new and better ways of approaching the modeling. Certainly anyone who wanted to finish a car will have pressed on long ago! Sadly it has taken me a year to get to this point... :-)
(Hey, what can I say? Hope it's been helpful... I don't get a lot of feedback, but the hit counter goes up!)
With this in mind, I'm going to cease with the step by step ordeal I've been putting you through, and continue on with a few thoughts on how to approach different aspects of the interior. By now, most people having read this far are likely better HyperNURBS modelers than me, so this more generalized approach shouldn't leave anyone in the dark.