Right, well as they say - if you want something done, sometimes you have to do it yourself
So - would anyone be for / against (asking David in particular here) if I went ahead and set up such a wiki? I'd be sure to clearly link back to the forums so as not to detract traffic away from here, and try to do it "properly" (proper domain name with a proper instance, not some unreliable free site with adverts left right and centre.)
The way I'd see it going would be that it'd be a subdomain on my existing site while it started with a few select users writing a few articles, commenting and helping to improve it. When we felt it was ready, I'd register an appropriate domain name, transfer it across and it'd then go live (there's no point making a huge announcement about an empty wiki!)
I've got a couple of spare days coming up hopefully, so if the answer is yes I should be able to get something up and running fairly quickly.