Glad to see the mapping file being well used. I would change things a little though.
1) Having the "texmap" folder outside of the "textures" folder forces you to use an absolute path in the mapping file, which isn't ideal. I'd stick that folder inside the "textures" folder. Also I'd call it snarsky, rather than texmap to make it very unlikely that other textures will conflict.
2) Glidos can read several mapping files, so I'd split the current one into one per level, calling them just level1map.txt, level2map.txt,... or caves1map.txt, vilacabamba.txt,... (which ever we can all agree on). Then users can mix and match levels from different authors without moving everything around.
3) Also would be worth putting copies of the mapping files into the snarsky folder. They would be unused there, but there could be a bat file usesnarsky.bat that copies the mapping files out to where they will get used.
If we obeyed a convention along these lines, users wouldn't have to worry about conflicts so much I think.