Well KiKo not many people release their .map file upon release of their map but if they do I would hazzard a guess that they do at Wacko's recycling bin http://www.planetmedalofhonor.com/recyclingbin/
He may/may not have what your looking for but its a very informative site and i'm sure you will learn plenty.
I believe that lizardkid speciality is in sp maps so maybe its wise to ask him.
You can also use a "decompiler" on a .bsp file. It will create a .map file, but it will not be good for recompiling without hundreds of hours of work. Mostly it is used to study how things were made and maybe copy a building or bridge. Here is a site where you can download a decompiler.
When a map is compiled, it changes all faces of a brush to individual planes. (flat, paper-thin pieces of solid with a texture on them) On a normal brush, a compiler would result in 6 planes for each brush. When the decompiler goes through, it finds all the planes and creates a brush out of them. meaning that you'll have roughly 6x the number of original brushes. afaik lod doesnt even show up after being decompiles, and some textures are missing.
it's only good for getting the general idea of a map, trying to mod it directly from a decompiled .map is near impossible at best.
I believe it was MPowell1942 who decompiled the Hunt and it took him 300+ hours to fix it.
Since most SP maps are just a new mapper's first test maps or learning how to map, the authors usually dont keep the .maps, so your best bet is to just noclip and notarget around looking at the brushwork. i know it isn't perfect, but it's probably the only way.