One thing that is often forgotten about higher resolution sensors, they are less forgiving. Not only do they magnify the detail, but they also magnify any imperfections, be it slight motion blur or lens quality. There are a number of higher grade lenses which outresolve the 40D sensor, but the 7D is able to outresolve those same lenses. I owned the 40D before the 7D, and there isn't really any comparison. Yes, the images appear softer in 7D RAW images, because as Neuro said, you're looking at a magnified view. 7D RAW images can accept high levels of sharpening in Adobe Camere RAW, often up to to 75 or more (I've even pushed it to 90 just to see what it looks like), if you shapren that much with the 40D, you are likely to hit problems. As a standard, I set the sharpening on the 7D at 40, instead of the default ACR of 25 and most files then look fine, although, even the slightest motion blur is visible. With a static subject on a tripod, the 7D is far superior to the 40D in my experience. Granted it doesn't match the 5D MkII in the same circumstances though. the other failing with the 7D is the increased diffraction limited aperture problem. You start to see softening from the effects of diffraction quite a bit earlier than you would with the 40D and it is easily visible to me by f/11 and by f/16 it is irritating (a bit like f/22 was on the 40D). This was my main reason for getting the 5D MkII, saving the 7D for fast moving wildlife or when I needed the reach. I tend to use the 5D MkII for macro too, both for use of narrow apertures and because of the better IQ. For studio work though, from my limited experience, you're often around f/8 anyway, which shouldn't be a problem.
I have only done one studio shoot, but unfortunately, I just double-checked and I used the 5D MkII, so I can't help with links. You're welcome to look on my website or Flickr account at any wildlife shots for examples of what the 7D can do in that setting. They're relatively low resolution on Flickr and you can't see the full size on my website, but I should be able to set something up if you really want to look. I send most of the images I feel are good enough for my website to stock sites and they've never had a problem with image quality (well, except for one 40D image that was described as soft or lacking definition, but it was a mist shot, so it was supposed to be