These come up on eBay from time to time.
You can also find other manufacturers' versions, though the Hazet is nice. Volvo tool number 9995196 is the Volvo version and also works well.
Baum Tools sells one - may need to call for price.
http://www.baumtools.com/shop/15cyli...l#.WEidjLIrJpg
A tool for Audi 5-cylinder gas or diesel engines will work. Tools for the 4-cylinder engines, like the regular 2574, are similar but not close enough to use.
As a last resort, a few folks on here have them and will loan. I have a spare that I don't want to sell but have made available for use in the past.