There has been some progress on calculating the display image tiles, position, etc which is key to enabling proper pan/zoom using - the Moon map now has 'live' coordinate calculations, and very basic up-down-left-right to try.
To get an idea of what the Base4/Binary numbers mean, read about using a Binary Coordinate System and how it is applied in the Virtual Earth tile system (hint: qrts == 0123).
As for the Venus map...
...it doesn't pan yet, but all the images were custom-generated^ using this quadkey map-tile generator. It's only about 100 lines of code, and seems to be limited by the maximum image size
Bitmap resized = new Bitmap(imageSize, imageSize); //16384
All three 'venus maps' were generated using that code.
^ the moon sample currently uses tiles from Google moon.