I've figured out a simple way of 'repairing' the original Philips 6604 bulb from the V35 that is no longer available anywhere on the planet a far as I can tell - and hasn't been for many years.
I've been all over the internet to see if anyone has done this but can't find any evidence of it. It might just get your Leica V35 up and running again if you haven't been inclined to spend $175 on a specially-machined part so that you can fit a more modern bulb.
The process is explained on my blog so please take a look and let me know what you think. It works fine for me and I'd be interested to know how you get on if you decide to give it a go.