Do you think this really needs a whole new token and protocol? I'm not seeing it.
You can basically do this in a plain text document. "Joe owes John $100 by June 23rd."
For a bank or some other institution that issues credit regularly, the blockchain might not add any new features... since the whole point of blockchain is trustless applications, eliminating middlemen, right? and in the case of a bank issuing credit, the bank already acts as the trusted third party by default.
In the example of Neoxian's loans - a simple steem post accomplishes this task just fine. Why issue a whole ERC-20 token around it?
I guess a protocol allows for more complexity, although it's arguable that one should have avoided credit facilities if it involves a complicated arrangement lol