During a holiday in the belgian Ardennes, I lived in Bellevaux. A small village outside Malmedy (~20 km from Spa Francorchamps!), but with it's own brewery.
The Bellevaux Black is a fantastic black beer, tastes a bit like Guiness just without the creamy feeling when drinking it.
Unfortunately, it is not possible to purchase it outside the Malmedy region (as far as I know - if it is, TELL ME!), but if you are in the area, do yourself the favour and visit Brasserie Bellevaux!
http://www.brasseriedebellevaux.be