I took a better look at what was happening in cshell.dll and found out that it uses DirectX 7 to capture images like those in the load/save screen. DirectX 9 or above works differently and has to "emulate" DirectX 7 functions, this is why its slow. Unfortunately there is no easy fix for this.Here's my final cshell.dll (load/save time has been fixed):
http://rapidshare.com/files/133809664/cshell.rar.html
Basically anything to do with capturing images has been removed and hence you will only see a black image in the load/save screen and simmilar. This is graphical only and wont ruin gameplay.