This one is more of a setting question; do lightning claws exist outside the Space Marines? I noticed in a playthrough of Dawn of War recently that Imperial Guard commanders can be equipped with them, but I'm leeray to take a video game as the last word on canon in a setting. =P Would be nice to have a pair, though~
Also, have Necrons been statted at all in any of the 40k RPG line? I don't own much of the series, but to my recollection, I've seen everything but them and Dark Eldar in the books (and even then, I recall a lot of the Eldar stuff in RT looking a lot like Dark Eldar gear, and things like Splinter Rifles implying they are about).
Also, what is most peoples opinion on how 'un-noticable' you could have cybernetic replacements? Does the Imperium have the technology to pull off things like Doctor Octopus level Mechadendrites which could be hidden under bulky clothing? And would even older cybernetics still be blatenty visible, like the 'half-jaw replaced with metal' look that Techpriests/Explorators have? Trying to find some fluff ways to describe my Explorator, and with stuff like Agility 43 and most of all his other abilities at 40+, was tempted to explain them as getting some older, less clunky Mechanicus Implants.