Orange peel is the texture you get when you paint and don't sand the first coat properly. It causes the paint to build up and it looks like the outside of an orange.
For your selling rigs what your doing is fine, as getting rid of orange peel and getting a mirror/smooth finish is a ---smurfette---....
For giggles.....
Prime, let dry, and sand, then prime again, and sand with a finer grit sand paper.....get you some tack cloth and wipe it clean....
It should feel really smooth to the touch....first coats should be light, then cut it back with a finer grit sandpaper, then paint again and if you do it right no orange peel......Let dry
Then hit it with like 4 or 5 coats of clear, wet sand, and then you can hit it with a compound, swirl x and then buff with wax......mirror like results....
This is sick....
http://forum.arcadecontrols.com/index.php/topic,94891.160.html