Before you end up duplicating work that's already been done, you might want to check some of these first. There are hundreds of screens available from several different authors.
http://www.subsim.com/radioroom/down...o=file&id=1056
http://www.subsim.com/radioroom/down...o=file&id=1057
http://www.subsim.com/radioroom/down...o=file&id=1058
http://www.subsim.com/radioroom/down...o=file&id=1059
Also quite some time ago I created a randomized loading screen mod that uses SH3 Commander to put up a new set of screens every time you load the game. I created no screens myself, but it uses 100 different screens from several different authors.
http://www.subsim.com/radioroom/down...o=file&id=2822