Shanghai GP3. Yes, I have about 20 rolls in my freezer. Only used 3 or 4 so far, but so far it looks OK. There are numerous eBay dealers in Hong Kong and mainland China, but the price doesn't vary a lot - they are all cheap. Be aware of a couple of quirks:
1. the backing paper is black with faint grey numbering, so it is difficult to see the numbers if you are using it in a red-window camera.
2. the tag at the end to lick and stick is not worth the saliva you put on it, because it just won't stick. If you are going to change films in the field take a small supply of small rubber bands to secure the used roll.
I have developed my own in Rodinal, but you can use almost any general purpose developer which does well with ISO100 film.
Cheers, Peter.