Hey,
I was just started using power suits in SMP survival and it is absolutely awesome! I think this would be a cool small feature. The ability to toggle on/off for a module that affects 2 or more suit parts, such as transparent armor. I like having just the chestpiece on me, and sometimes the active camoflage feature is quite useful. I think a great thing for the key config system would be to add each armor piece in and you link the armor piece to a key, then link it to a module. So you could link a transparent armor module to a chestpiece then to the key, so that only the transparent armor for that bit turns off.
Thanks for all the great work you did on this mod, I really hope this small feature can be added in a future release