They look quite cool, HC. Not quite my style, I like lots of colour popping off the unit, but I can see it being a very effective look. I would suggest a design on the shield though, I think it will look too whitewashed without it. Something subtle, just enough to break up the solidity.
Interestingly enough, the effect you have on the sword is kind of what I've been looking for, but in regards to my Sternguard's bolter casing! I figure century-old veteran marines should have funky weapons, and marble texture is pretty ostentatious hehe.