@knowhow
Just so you know, I'm planning to input the idea that accounts will only have one owner, the one that made the account

This again for security reasons ^^
So whatever your planning on doing, do it quick ^^
In my honest opinion, selling/buying accounts is a no-go :p
(A simple example would be, if ever a btc-address is used on multiple account, both will be locked until further 'research')
How would you go about finding out about multiple owners from buying and selling? Some accounts may be shared, or a person may access it from different IPs, depending on where they are. If that's how you plan on cracking down on buying and selling, it could disrupt the game for many honest people