The problem with successively smaller objects, like in the case that Shonner has done, is that Carrara is a limited ray depth of 25'ish. I say ish as I've tried this with one of my images and I had less because Carrara would stop after a certain point. Probably due to some tolerance on transparency. This sort of limits how 'translucent' you can get. Make the steps to the smaller objects too much and it'll be noticeable. Make it too small and there won't be much depth to the translucency. Also it can be really hard to make sub surfaces if they aren't simple like a cube or sphere. Another draw back is that if you look close (or if there is something behind the object) you'll see through to what's behind the 'flesh'. Not really want you want but not much to get around it. However if Carrara did allow for a significant increase in ray depth, super fluffy clouds could be made but that's a different issue.