Wwaswas.
Thats a good idea and I see the attraction, but wireless would require a power source and would likely add weight, which as we know, for a helmet light is a primary consideration.
Then you'd also have to cater for two people using the same brand and model of helmet light, not operating each others light
The unintentional operation by people in close proximity, using the same equipment as you, is something the wireless bike computer companies have had to deal with.
Perhaps a good compromise would be a remote switch on a long fly-lead, so that you could attach the switch to your back pack strap, in a similar fashion to those camel back bite valves.
I think the helmet Light Chipps reviewed in issue 61 had a remote switch on a long lead, and the 401 can use a remote switch too.