Feanor

I am way too lazy to do any major work but I have "customized" some details here and there on this blog.
I just realized you may find useful this little trick:
How to make the page background stay fixed while the blog scrolls.

It is a bit tricky because it depends on the "template" you are using, anyway you should probably add this to your user CSS file:
body{background-attachment: fixed;}

In some templates (like mine) you must also add:
#wrap0{background-attachment: fixed;}