Spoon USED TO make wheel nuts that fitted oem wheels in gun metal colour as mentioned, these have now been discontinued though....
You can get 2 choices in wheel nuts for stock wheels:
1. Standard chrome finish (comes with the car)
2. Black wheel nuts, as found on the 91-96 run of the NSX, on the new JDM civic type R FD2
The NSX/FD2 wheelnuts are NOT cheap though from honda, NSX ones are about £5 each including VAT and the FD2 ones are about the same price, you NEED the part number for this as i tried giving them the chassis no. for my dads FD2 and they came back to me with silver nuts which they had in stock durrrrrrrrrr
i was going to get a set of black ones, but at £100 for a set of wheelnuts.... i'm sure that money can be better spent elsewhere
I did read on a different forum about someone having their stock wheels modified and the wheel nut seat bored to a taper seat so they could use aftermarket nuts, would have to be VERY accurate though and to be honest doesn't sound that cheap/safe!!!
If you wanted something different could always run ARP extended studs and open ended nuts from honda? That would be kinda cool