Wardrobe lighting problem

70mm for a reed switch is pretty damned far - I doubt this will work unless you're able to get one part of it in closer (maybe the reed part on the closet side, right next to where the door travels, and a beefy magnet on the door?). I use reed switches, and found I needed to get the magnet (a rectangular rare earth one of considerable strength) like 1 cm away from the switch for reliable operation - though my reed switch might be less sensitive than some?

I see a few options:

1. Reed switch, with some bit of cleverness to get the magnet and switch mounted.
   
2. LDR in the bottom of a can or tube facing out and located close to the door. This, of course, will present a problem if the lights outside the wardrobe are off, but you still want light to find things inside it, though I'm struggling to think of a case where this would matter. In any event, like any sort of light sensing, the exact position of the sensor, and the size, shape, and orientation of the light-shield around it will make a big difference.
   
3. Physical switches, probably a micro-switch of some sort. (wouldn't this be a good use for one of those micro-switches with the roller-wheel on the end of the arm? Or are those scarce/expensive if you don't have them on hand?)
   
4. Use a PIR motion sensor, on the reasoning that things rarely move inside a wardrobe while the door is closed. Of course, you'd need to give it some grace period, otherwise you'd have to dance and wave your arms while choosing what to wear.