Indeed I also thought about modding my 7d. But the downside is pink pictures when doing ordinary photography.
Custom WB is not the solution as I sometimes use another WB for e.g. incandescent or LED lighting which presets do not work anymore.
And with proper processing I can rather easily get the Halpha nebulas despite it is blocked by 70%.
Here an overview of the area between Deneb and Gamma Cygni.
http://www.skysurfer.eu/skypics4/lar...us-nebulas.jpg