Holy smokes John, where to start???
I'm 100% in agreement of a digital display of the codes - they could appear right on the radio display. GM has already used the radio display as the input for other electronic commands. The radio could then briefly interupt the music to show a code periodically.
But I'd stick with analog guages for the basic outputs. They are more reliable after 10 years, CHEAPER, and can look really cool if you try. Computerized controls only where it makes sense cost-wise. Built it reliable enough and you don't NEED trouble codes. The first 100 years of cars got along fine without them.
I'd keep the exterior design as simple as possible to reduce costs, including ripping off popular styles from past vehicles that were changed before consumers got tired of them. I'd use major components from known reliable manufacturers using existing tooling. Assembly would keep in mind the ease of cleaning to reduce the salt & rust traps.
Shoot me for this - but smaller engines bolted in too. Most of us aren't pulling boats every day the key is turned. These engines would be less than 3.0 liters. I'd recognize the foreign oil dependency as long term trouble. The engine would be the simplest design not seen since the slant-six Dodge dart. It'll be hailed as the new 'bulletproof' engine that any Joe/Angelina with a reasonable knowledge and box of tools can tune up, repair, modify himself/herself.
Keep the full frame design if possible.
Strive for 24c/29h mileage. Minimum.
Offer it in three or four colors maximum. Maybe two interior colors. If someone likes the vehicle but wants it in 'burgandy mist' or 'polynesian blue' print up a directory and directions to custom paint shops in their region.
Everything will be standard - no options except automatic or six-speed.
Let the customer add their own stuff aftermarket if they want.
Safety features would be just the bare minimum of what the laws require. People have to realize that they are on the road in a moving mass of steel and should drive at a reasonable speed given the conditions. By putting all the crash features in today's cars the price has gone way out of line and makes drivers feel overly secure and use less common sense. Not to mention the added weight's affect on mileage.
And last............offer it in a price that initially will be at cost, until the tooling is paid for and suppliers are able to ramp up production volumes at a reduced price. Entry price about $12,000 or so. With a five year basic warranty with no BS exceptions. Outdoor outfitters of gear and clothing have long ago learned that an unconditional warranty keeps people coming back, and gets new customers. Then wipe out the competitor's $25,000 - $30,000 sales when people realize that an SUV half the price is almost as good or better.
The theme of my engineering would be to learn a lesson from the past: The Model T and the Volkswagen Beetle could be purchased by just about anyone who had a basic job without being in debt for years. They had the right amount of utility without going overboard in design. And last, the components would be recyclable after the vehicle is worn out in about 20 years - 275,000 miles or so later.
Tom