Here are some basic customizations you can do (removing sports strip, TV strip, and MCE Spotlight): http://www.mediacenterguides.com/index.php?title=Menu_Customization.
http://mediacenterguides.com/custom_ui *Edit* - link has been changed.
Here is more stuff you can do, I haven't tried anything from here, so I can't say for sure how well it works - if you have any luck, please report back: http://blogs.msdn.com/astebner/pages/customizing-the-windows-media-center-start-menu-in-windows-vista.aspx
The simple answer is 'No', to be honest.
There are some things you simply can't get rid of in Media Center - that's the way it looks, and we are pretty much stuck with it. It's not designed to be user-modified in that way.
There may be tricks that will be discovered in the future, but right now nobody seems to know of any.
Could I ask WHY you want to do all this to your Media Center? Is there any major advantage to your particular situation/design?
I HATE 'Sports' - I'm not a sport watcher, so it's a complete and total waste of time for me.
I must admit, I wouldn't mind being able to run the Media Center in 'Simple' mode, with the Tasks menu completely hidden other than having the option to turn the thing off and perhaps update the guide.
So jhoff, you don't use Pictures + Videos? It's the feature I use much more often than any of the others.
IgnoranceIsBliss:I HATE 'Sports' - I'm not a sport watcher, so it's a complete and total waste of time for me.