I don't really want to read all 15 pages of this so this may be a little redundant ( and possibly repetitive) but:
Why not have the user make thier page (with a perma-username) when they choose, so like have a link in your account options that explains it all and that after it is made you cannot change the URL.
This would also make it so people who dont use their accounts anymore dont have a page
Also, it would give people a chance to figure out a good name before making their page.
and what would you do about people who make tons of pages wiht different accounts and then never use them?
It seems like this would be a bigger problem with pages than with how they are now..