In my younger days in the last century, a lot of us motorcyclists used to swap over to a different form of wheels for the winter. They used to have a heater (of a sorts), and were grossly unstable over 70mph. But they did allow you to carry the kids in comparative comfort (rearranging internal organs was the order of the day on B class roads).
http://en.wikipedia.org/wiki/Image:Reliant_Regal_3-30.jpgYou were allowed to drive one if you had a full motorcycle licence because it weighed under 8 hundredweight (896 lbs) and was classed as a tricycle (bike with a sidecar).
I still see a few knocking about, even though they stopped production a fair few years back.
They were affectionally known as 'Plastic Pigs' because of the fibreglass body.
The all aluminium four cylinder, water cooled inline engines started off as 600cc and over the different ranges finished up at 850cc. The engines were used in a class of motor racing, the Formula 700 (the engine converters in the mid 70's were based in Market Drayton, Shropshire, just down the road from where I used to live, and I had mine tuned there, coupled with a higher ratio back axle, I could cruise at 90 if I felt brave enough). I was pulled over by the fuzz a few times, who couldn't believe that a 'pig' could go that fast, I never let on and blamed it on a tailwind or going downhill, they never noticed the large forwards facing Stromberg carb with a big bellmouth (you could only see part of the engine thru the top hatch, and if you wanted to do a lot of engine work, it was easier to drop the engine onto the floor, and lift the body over the top).
I also worked for a while making 'Mountain Range' fire engines (the smaller ones were based on a special six wheeled 'in house' conversion of the Range Rover, one of those would please Crew Cab), and the same basic engines were used on the portable pumps carried on board, two men could carry them easily, because of the light weight.
Getting away from the post slightly, just reminiscing, as we all do.
John