I like a lot of the ideas bounced in this thread & may even have a go at a few of them myself, especially the suggestion of recording your own clap & maybe a few others & layering them all together!
However, until now I didn't really like what I had so I found a couple of samples I liked the sound of in my trusty old Roland JV-2080, played with the pitch & envelopes & then sampled those into Session Drummer 3 where I panned & layered them slightly out of sync & slightly different pitch to each other to give more "grit". They sound fat & funky now so I've got what I was looking for.
Basically, the samples in my JV were gritty noise samples, but I can't remember whether they were originally a percussion sound or a sound effect. I can check tomorrow when I'm back in my studio if that helps but I found noise samples to be particularly good at this sort of thing!
BTW, I also filtered out the low-end to help them sit in my mix better as there was quite a lot of low end noise and crunch ( I expect you probably know that anyway).
Hope that helps...