Hi Alaska,
I am of a little bit different opinion here.
1:4 ratio would require extremely low RPM's on the internal combustion engine. Cruising speed for my car in overdrive right now (I have a manual transmission) is around 2,300 RPM's. If I were to drop that by a factor of 4 it would be somewhere around 600 RPM's and be very rough. The engine would also have very little power as engines are known to produce their best power in a "bell curve" near the top end of their RPM range. I think somewhere around 75% of the way to redline is where most will hit their max torque. Max efficiency may be at a different spot, but definitely not at the LOW end of engine RPM's.
What I might suggest is a way to have an engine detect "load" or torque requirements and start shutting down cylinders. Let's take a 4 cylinder car for example. I would think in today's technology it would be a fairly simple matter to allow the engine to start shutting down cylinders as torque requirements drop off. I'm not suggesting that the engine just shut down specific cylinders, but rather that it rotates so that each cylinder gets proper use and even wear.
In other words if the engine determined that it could run off 3 instead of the 4 cylinders as you are driving down the highway, it shuffle things around so that instead of having all 4 cylinders in use every 2 revolutions (2 revolutions per 4 cycles), you would only have 3 cylinders in use every 2 revolutions. It could easily rotate the OFF cylinder through the engine so that each cylinder received the same utilization and engine wear.
As a further example if the engine determined it could run on just 1 cylinder for the current stretch of roadway, then the system would rotate the ON cylinder through each of the 4 available cylinders in the engine.
This strategy would achieve your same 1:4 ratio that you were trying to express in gearing, but it would do it in a manner I believe to be much more conducive to the engine's operation.
I'm no engine expert, but I imagine this would work far better. In fact, you could even have it drop down below a 1:4 ratio in that 1 cylinder could be fired whenever power was needed, just like the old Hit & Miss engines.
It would be very interesting to see how this would play out indeed.