"It would shock me if the car came off the lot like this in 2003 because nobody would buy it..."
Good point. A bouncing steering wheel at idle is not normal. I would take it today to a Honda dealer or a good import garage and let them see it. Didn't the used car place give you a 30 or so day warranty? If so, and even if they didn't, you might convince them that there is a problem if you have an estimate from a Honda dealer. FWIW my 2002/4cyl/auto with 56K miles doesn't vibrate like you describe. I test drove an older 4cyl Volvo a few months ago that vibrated hard at idle, but it had obviously worn engine mounts and a backfire.
