Many thanks to all for the feedback and comments, it's made it even more worthwhile.
Still not sure on how to wire in the new toggle switches, and a big problem is goint to be the terminal that comes of the bottom corner, still nothing a dremmel shouldn't be able to sort. I've got an old multi volt transformer so I might have a bit of a fiddle and see what I can come up with. bit loath to suck it see on the PC itself incase things go POP.
LED wise the ones I have from "M" are intended to replace the blue power, HDD and reset lights currently on the rig, It's because the power for these lights comes straight from the mobo at the power block terminal that i'm hesitant to suck it and see there either.
All I need now is a new GPU to replace the 8800GTs I have in place, but waiting to see what Nvidia are going to release, hopefully before too long??