Right now wheels options that exist for the NSX I have found.
HRE, few examples of their P200 series wheels in 20/21
Vossen has done a forged 20/21 set
Forgeline built wheels for a race car and the look/weight seem like a good option to me but in 5 lug obviously.
http://www.forgeline.com/customer_gallery_view.php?cvk=1722
Advan has the Advan gt in 20/21 that science of speed has on order, some sets arrive in march I believe.
Titan7 has a wheel set in 19/20 that will be available for the NSX
BBS currently doesn't really have a fitment for the NSX, I did talk to them but the fitments you see on tirerack would really be a step down from your factory wheels.
I'm leaning towards the Forgeline wheels. Lots of great options though.