Doing some grid-based lighting tests led to some interesting discoveries regarding normal maps and how they can be used with Fusion 2.5 - currently the normal map shader is loaded on every tile, not ideal but it maintains a steady framerate on a good system. It would be worth trying to tile and render the normal maps onto a single surface in the shader, download the example and feel free to do so! Further shader manipulation may take place in future.
Check out the source (it's free!) here: http://clickstore.clickteam.com/open-source/platformer_nomal_maps
Some screens (beware! large gifs):
The above screenshot shows added shadows using one of two examples available on the Clickteam forums.
A tutorial video (short and easy):