Hi Jake.
You can see bones in a render if you use SHADED mode (as opposed to FINAL) and have the object selected before render.
I don't know how to make a slider that will control the speed...that is a good question for our rigging gurus. To get an animated speed-up I would animate the bone directly in the choreography- or I suppose...it could be done in an action too, that would make it reusable. Select the prop bone and change it's property to EULER first. Then go to your end frame and grab the roll handle and give it a twirl in the direction you want it to spin. Now, you will take over animating in your channels editor. Find the channel for that bone, and in particular- the roll handles axis (Z). Adjust the bias as I have in the attached image for ease in and out. You can also easily control the actions length and overall rotations from the channel window.
Happy flying.