I'm a bit late to this tread by about 5 years!!.
I too am greatly disappointed in the lack of female bodybuilders not doing nude though there are some fbb'ers who have done the odd nude shoot/implied nude.
I have been collating them for a few years & have a Flickr profile dedicated mostly to female muscle nudes, though I cannot add any more these says due to the fact that you must pay for a Flickr account if you have more than 1000 images!.