As noted by W T, the individual switches are no longer stocked by North American suppliers. You need to purchase the whole package of switches, Acura calls it the Switch Assembly - Combination & Column Unit, for a cool $1700+.
1995-2005 Acura NSX Switch 35250-SL0-A02ZA
acura.oempartsonline.com
If you go to Amayama.com you can sometimes still find the individual components listed; however, because of the whole left / right steer thing you need to be careful with part numbers. Amayama technically does list parts for the North American market. However, in the case of the NSX, 95% of the parts (and part numbers) match between North America and the rest of the world. The steering column being on the other side may be one of those oddities. On the North American web sites 35280-SL0-A02 is the light switch; however, on Amatyama 35280-SL0-xxx appears to be the wiper switch. The headlight switch selection is confusing. For manual transmission cars there is both 35450-SL0-013 which appears to be unavailable and 35450-SL0-003 which is listed as available for around $300 US$. The website does not give enough information to determine the application as both switch numbers apply to 1995 manual transmission cars.
The slightly good news is that Amayama lists the Switch Assembly - combination with the same North American part number (which eliminates that part number confusion) for about 1/2 the cost of the North American vendors.
Honda 35250-SL0-A02ZA (35250SL0A02ZA) Honda 35250-SL0-A02ZA (35250SL0A02ZA). New & genuine Japanese car parts. Fast shipping. Low prices. Request a quote from Amayama Trading Co. online.
www.amayama.com
RockAuto claims to have the headlight switch available.
However, the down side is that the RockAuto price for the headlight switch is about the same price as the complete combination switch assembly from Amayama. Given the Exceedingly low production numbers for NSX parts I expect that the WVE switch sold by RockAuto is the OEM switch in a WVE box.
So, the headlight switch might be available for around $300 from Amayama if you can sort out the part number mystery (or just take a flyer and order 35450-SL0-003 and hope for a good outcome). Or you can order the complete 35250-SL0-A02ZA from Amayama for about the same cost as the bare headlight switch. Of those two options I know which one I would pick.
If you contact Mita Motorsports, they are located in Japan and specialize in NSX parts sales to North America. With their experience, they may be able to parse the Honda parts numbering system and source the correct headlight switch for your 1995 at a reasonable price.
Manufacturer, Designer, Renovator. MITA Motorsports is a dedicated parts manufacturer for enthusiast favorite vehicles. Home of OEM+.
www.mitamotorsports.com
A final note, if you just have an electrical issue, this may be fixable by disassembling the switch and cleaning the electrical contacts. Of all the posts that I have read where people have experienced problems that might have implicated the headlight switch the problem has not been the switch. Of course, if you smacked the switch and broke the housing, then a new switch is in order.