Awesome maps. Couple comments/thoughts...

Us Coloradoans tend to think green = trees; white = alpine tundra or grass. So in the mountain areas the white areas tend to be the area above treeline.

But that said, it looks a lot like the USFS topo maps in the areas I've looks. It is a fantastic map to look at!

I've been working on a similar project, but using the original USGS topo and "updating" it overlaying OSM, hillshading and perhaps some DLG files...

Did you consider using the USGS DLG files?

In response to Leigh, I've also been working with the Canadian CanVec files, which are identical to their 50k topo maps, (these are the files from which the topo maps are made)....any thought on creating the canadian topo maps?

"When you load multiple topo's at the same time, you'll notice that the white borders around each map will overlap with the one next to it. I'm currently writing a program to get rid of those borders, but for now, you can work around it by setting each topo layer as partially transparent. You will notice that adjacent maps line up exactly. MUCH better than the terraserver based WMS layers!"

One non free program I use is GlobalMapper. It has an ability to crop the collars off to display the DRGs next to each other. Another thing, keep in mind the DRGs all have a set lat/long, so maybe using a database with this info you can get them to cut right. Are you writing a stand alone program or a plugin for qgis?