This is definitely something that we'll be tackling. I was going to do something for version 7 but it will probably wait until 7.1. The main reason is what I'd like to see is something just as customizable for the user as it is for the admin. Meaning, not only the option to turn sidebars off, but the option to rearrange things as well.
The main issue on this is the fact that some site owners don't want somethings moved. Like they may have a deal with a company for an ad but only if it's placed in a certain position. So we need to balance user flexibility and also admin control.
