Yeah my 59 Pontiac was the fastest heating car I ever saw. Below zero and heat would be coming out in a couple blocks both in the front and the rear heater. Can’t find many of them anymore though. Also my VW Bug with the gas heater was right there.
The idea of a block heater is nice, but that only works at home, where the car parks inside an insulated garage and isn’t really too cold over night. The problem is when it’s parked outside for 10 hours while she’s at work and the day’s high is -22F.
I remember reading an article many, many years ago about cooking food on the manifold and they had the hardest time cooking on large engines (the Viper was the worst) because the large engine never worked very hard and therefore never heated up much (or good cooling and too much thermal mass kept temps down), which is why I was thinking of a turbo 4 since the coolant runs through the turbo and that has exhaust running through it (obviously) so it should get hotter quicker.
Seat heaters are already in the Jetta, but once you bundle up, the insulation works to keep the heat out. 
I would love a heated steering wheel, but I’ve only ever seen those in an Audi, and that’s a bit out of the price range.
I was wondering about a 12v heater, but how much heat can you get out of the cigarette lighter? Remember, we’re talking negative Fahrenheit temps here with a 10 hour soak time. The car doesn’t warm while idling, in fact you can watch the temp gauge fall when stopped at a stop light or coasting down a hill for 10 seconds, so a remote starter isn’t going to help (unless it can enable the seat heaters, which would work on a retrofit, but new cars don’t energize the seat heaters via the remote start).
Thanks for all the replies, they’re great things to think about!
I think you are over-analyzing a little. A larger engine has more mass, more and larger cylinders firing, etc. so more to warm the coolant. With a diesel you have to remember that they run very loose and will not generate as much heat from friction as a gas engine. Forget the plug in 12 V heater. I tried one of those in my diesel one winter and did very little for me. Just get a regular vehicle with a V6 and you’ll do fine.
A larger engine will also typically have more coolant to warm up than a little one. Even the heater loop will have more coolant in it, and a big car or truck may have a larger heater core. I’ve noticed that my engine warms up a lot slower if I turn the heater on early. It still has usable heat fairly quickly, but takes a long time to get to full operating temp. The thermostat is good. It also takes a long time for all that coolant to lose heat when it sits after driving. If the cylinder deactivation is running, it definitely warms up slower as well. Oil quantity may be a factor too–since oil cools the engine directly, if you have 7 or more quarts of oil, you may take longer to warm up than an engine with 4-5.
As for the question about heated steering wheels, a quick Google search finds they’re part of the cold weather package on many current cars, especially luxury cars, but not exclusively. Living in a mild climate it’s not a feature I’d ever really considered. My current car has seat heaters, but the one time I was cold enough to use them I didn’t remember I had them. If I lived in a cold climate I know I’d just love them.