NiSpan C is the generic name for Elinvar Extra, which is a fantastic hairspring material. It's more magnetic than Nivarox, but less than steel. It looks like British precision springs has some springs in the range that might work with your Oris that are NiSpan C.
Otherwise at that quantity you can talk directly to Nivarox, or try www.atokalpa.ch, www.atlasmicrotech.ch, and www.precision-engineering.ch. Even at 1000 pcs, you will probably shocked at the price, definitely more expensive than the British company! Like 5-10x more.
Are you planning on vibrating these yourself? You will need collets and studs, which the traditional type are hard to get now. The above Swiss companies can collet them with modern collets, at an extra expense of course.