Yeah, Dogs on Acid is pretty much the only place to go for DnB loops. But other than stuff you might find from producers like Cause 4 Concern, etc etc. loops are garbage anyway (who isn't sick of the Amen break by now?) -- a real cheap and easy solution would be to get yourself the natural studio drumkit from http://www.naturalstudio.co.uk/ and just make them yourself. As far as free drum kits online, this one just absolutely destroys everything else out there quality-wise. It's a minor hassle setting up a "master" track in Fruity or whatever you use with every sample (considering there's about 20 samples per drum) but once you have that saved you can rock the world.