There is not a one-stop customizer for Manila. Plus customizing depends on which version of Manila you're using.
That said:
Use HDWalls to create the wallpaper with your photo's.
http://forum.xda-developers.com/showthread.php?t=503511
The cab for no-curtains is located here (WM6.5 only).
http://forum.ppcgeeks.com/attachment...7&d=1257101784
Search under the TP2 themes for taskbars and etc...