Hey Aaron,
Sorry for the late reply...
Yes you do have to write a shader for dynamic bump maps.
There is a cool shader pack written by the folks at noolness.com
It contains Normal/parallax and relief shader's for use in TGEA.
Clickie
My understanding is that, In theory, if you incorporated the height map info into the Alpha of the Atlas texture you could use relief or parallax maps too.
If for some reason the pack becomes unavailable email me and i will send it to you
Does that info help any?
*edit*
I think that using detail maps is a poor substitute for a high res. image as they are too generic and do not represent the true detail of the actual texture used on the terrain and would love to be able to use a high res. normal/relief or parallax map, though the processing required would be greater. :S
My hope is that when my game is released, the average users hardware will be up to the task.