Apologies if this idea has already been hashed out before (did try some searches but maybe my Google-fu is not so strong).

I was thinking about the issues of ownership and virtual property and the following idea came to mind:

Consider a Bitcoin address that contains a small balance:

1ownerXXX 0.01

Now consider some sort of XMLish "virtual property certificate":

[property]
<service>WoW
 <item>Player
  <role>fighter
  <strength>1000
  <experience>10000
...
  <token>xxx123456
 </item>
</service>

and the use of the new "sign a document" feature of Bitcoin.
(so the above document is signed by owner of 1ownerXXX to prove ownership)

Assuming that the token "xxx123456" can be checked with the online service to verify ownership and validity then if one player wants to transfer this "virtual property" to another player one could send the property to an escrow (yes 3rd party trust involved here so some sort suggestions for a decentralised alternative solution would of course be welcomed) as follows:

1ownerXXX ==> 1escroXXX

After this tx occurs the escrow creates an address for payment which if funded with the requested amount results in:

==> 1ownerXXX ==> 1escroXXX ==> 1newowner
1payment ==> 1oldowner

and if full payment not met by agreed time then:

==> 1ownerXXX ==> 1escroXXX ==> 1newowner ==> 1ownerXXX
(and possibly 1payment ==> 1newoner as a refund due to insufficient funds)

The actual service (such as WoW) will decide who the "owner" of the virtual property is by simply following the transfer from the original address to its latest owner via the blockchain.

The main point here being to use Bitcoin blockchain as a way of showing proof of ownership of virtual property.

Has something like this already been implemented (and if not why not)?