I came across a site of Harry Clarke Illustrations. Plenty of images (63 from 'Faust' alone) at a decent size, though no images of the stained glass.
There are a few links at the site including this to a brief Harry Clarke bio where there are also a few images of the stained glass.
Seeing all this does remind me of the conundrum of Clarke that his black and white work is very strong, his stained glass work is very strong but his color illustration work is pretty weak. I've always wondered - why? I noticed this time that the color illustration work has a curious absence of black. Perhaps Clarke was an artist who needed to ground himself in black. One of the most striking things about the black and white work is how rich and expressive the black is. Certainly the stained glass works partly because, by the nature of the medium, there has to be black. Clarke was also fairly obsessive about incorporating that black into the design in stained glass windows. I've always felt this makes his designs stronger and the colors more vibrant. The color illustrations do not have that rich black to bring out the colors. The stained glass does.