I was mulling over this earlier this week. I think I already know the answer, but there may be something that I am not considering, so I'll just post it and see what happens. If you're bicycle does not come with a built-in dynamo, I know that you can add one for a relativey decent amount of cash, but is it possible to "hide" or place the cables in the dowtube etc. of your bike, so that they are not exposed, or is this not possible due to the welding of the framework that has already been done at the assembly plant? If so, how is it possible to do?
Just a thought.
If you've done it, please share your story, tips etc.