cool,
Changing the bootup screen was not as bad as I had expected. Great tutorial. The skimpy color palette sucks though. I tried making a new .act file from Photoshop but when I open it in HexEdit it is 304 instead of 300. So I tryed replacing it and my logo stayed therer but the gray background was a very bright red. So I guess it is possible to change that gray to a different color too.
And thanks for finding that login screen tif. I kept replacing the same one that I replaced in 10.1.5 and nothing was happening