Thread:Project:Support desk/Make all pages/main-namespace behave like categories/category-namespace/reply

Short answer no.

Longer answer: why would you want to? (I'm asking because there might be a better way to accomplish what you want if I knew the context better) There's lots of in built assumptions that categories are in the category namespace.
 * First and foremost, in the db we don't store which namespace the category is in in the categorylinks table (since its always the same one)
 * Links to categories are handled very specially - is invisible on the page because its a category link. If main namespace pages could be categories, then that'd throw off the whole linking to main ns pages things
 * There's probably many other assumptions made about categories that would conflict. Category pages are handled by different php code then normal pages, etc.