There may be some 12 volt heaters designed as cab heaters, I haven't seen any, but have never thought to look for them. These would draw a lot of current from the battery and probably end up draining it in cold weather. The cabin heaters I use are designed to use 110 VAC (house power) and generally have some simple brackets etc. to attach inside the cab. You plug these in the same way you plug in your block heater or battery blanket and they're usually thermostatically controlled to shut off when the cabin temp gets to a selected point - this keeps your cabin from overheating. The cabin is nice and warm when I get in & the battery is warm & in top shape, so it can turn the starter easy - so far, with this configuration I've had no early morning "starting anxieties".

Unless the outside temp gets really cold, I use a battery blanket and cabin heater on most of my vehicles - I just plug both in at the same time and since they both have thermostats, I don't need to worry about overheat. I just need to remember to unplug the cord in the morning before I drive away. These days, I just have a block heater on my jeep because it stands for long periods and if I decide to use it in the winter, I plug it in to warm the engine somewhat to allow the oil to flow better when I turn it over.

 

Correct, I have seen many semi-truck drivers use them.

 

I agree that a 12v cabin heater is not workable. As for the 110 v variety, the hassle of running extension cords all over the place and then having to worry about an electrical appliance running unattended inside the truck all night just isn't worth it. A remote starter is a far better solution if I have to have warmth when I climb in.