the chrome lugs may look out of place on dark wheels... but if you paint them the paint is just gonna come off when you tighten them...
whats "the center part of the hub that fits in the middle of the rim"?? the lug cap?? or the small 2" circle in the very center of the rim, where you can see the half-shaft bolts?? If its the later of the 2, i'd say to find some sort of "cap" for them... like "H" caps painted the color of the rims with a white "H" emblem...
BTW- PICS, PICS, PICS!!!