As for motor assisted, if you're going to turn a bicycle into a motorcycle, why bother with the scotch tape and bailing wire? Just get a motorcycle or a scooter and be done with it.
While for shorter distances (up to 10 km one way) I would recommend anything BUT a road bike, for longer one that is the best solution (or a recumbent
).
One more thing to consider: weather.
For rides up to 5 km, you can get away with anything.
For rides up to 10 kms, you need decent clothes, but however severe weather, you are only exposed for under 30 minutes, so if you start getting cold toes, fingers - it's not a real problem.
For longer rides, you need really good clothes and shoes - for rain,snow, strong wind etc. It will affect you.
These are just things to consider - not trying to discourage you - GO FOR IT. Just have it all in mind when planning - time, clothes, gear, bicycle. I love bicycle commuting, wouldn't have it any other way.