Also, the camera on the tablet I'm using SUCKS. I can't take away the fuzzies. GIMP's sharpen tool does nothing. Eventually, I'll post better versions once I've access to a decent scanner.

Did you try the Unsharp Mask?

I have found it more useful in photos. Never had any luck with the Sharpen tool at all.

Another thing that will, in some images, give an appearance of sharpening is to use the Bump map.

Spherical is better than Linear usually for me. You need to try it out and see also if "inverting" helps the look. Does occasionally.

Use the default on depth (3). It really doesn't do a lot but can be really effective in sharpening and images appearance.

It is simply exaggerating the dark pixels or, inverted, the light pixels. A little bit goes a long ways.

I think I'll just wait to get better scans. Garbage in, etc.