I picked up a 95 4x4 dodge with cummins, auto, 3.55 gears for my wife a couple years back for $8k...had a 100k miles....very bottom of the doors were just starting to rust, but the rest of the truck was incredibly rust free (looked as if came from TX) and in nice shape.
Now, I end up using it more than my 01 powerstroke because it gets better mileage, more comfortable to drive, and is less expensive to repair. Granted, the 3.55 gears aren't that great for towing, but it does just fine...pulls 5 to 6k with no problems around here (I wouldn't go out to Western MD though) on the stock tranny. Kinda wish I waited to find a manual (could make it into one), but my wife enjoys the auto.
The 95-2002 powerstrokes and the 89 to 2004 ish cummins are shooting up in price rapidly, but you can still find a relatively low mileage one for decent money.
My edit - just saw that you need four doors and a 'good image'....the latter is a relative concept...I like older vehicles in good shape and my customers don't seem to mind either.