On eBay there is a seller "Lakes Graphic" that has a lot of Pacemaker parts. It is kind of hit and miss but I have seen bellows offered. You could try and contact them through eBay.
on ebay there's also a seller in China called "ecbuyonline2008" who list many different bellows - including Linhof and Horseman 6X9 bellows - from their feedback it seems like everyone has been happy with their work - and their pricing (less than $100 - delivered) is very good...
I haven't used them, but when I decide to replace the bellows on my De Vere 5x7 I'll gve them a go