I had never even thought of having a personal name with a slash in the middle before, even though I'm familiar with s/he and Lehrer/innen, etc. I'm learning so much in this thread! Thank you, ghoti and kaberett. :)

It seems to me that Daniel/le would be very elegant in general use but that computerised systems would have a hard time dealing with it.

Edit: where my mum teaches, in Essex, the kids pronounce Daniel and Danielle in the same way, so this example would work extra well.