I have posted the NML and NABC skins on the NML league web site, not far below the top. Just click on the link and the zip file should download. Once downloaded unzip the file to the OOTP5 graphics folder, then copy the logosmall and default files to the graphics folder, but before you do this you must either rename the current logosmall and default file or move them somewhere else for safe keeping.
Once the above is done just go into the game set up and choose the new skin either NML skin or NABC skin. They should work, I hope.
If you have any suggestions or problems leg me know.
Almost forgot the url is
http://www.nmleague.com/index1.html