I checked with Gene @ Malkoff and he can't do a custom On/Off tailcap switch for Fenix PD40R, so I asked what quantity would take it out of the custom category. I really want one. Anyone else? I'm sure they won't be cheap. Let me know.
The reply from Fenix was quick & negative. Two gents replied with different recommendations, a TK16 V2.0 and a PD36R. I reviewed them both and decided on the TK16 V2.0. It looks like it will work fine as my Scooter's headlight. It has two tailcap switches and will go to 3000 which I would only need if I drove the public roads at night. I still like the rotary level selection on the PD40R. Maybe someday Fenix will add a tailcap switch. I suspect that I'm not the only one who would like to pre-select a level and have the light "wakeup" at my desired level and be adjustable from there. I guess if neither Fenix nor Malkoff will do it we're SOL for now.
I keep inadvertently pressing it when turning on the light.