Bitcoins in my opinion is really not the right currency to be able to allow loans. I personally feel that trying anything like this with bitcoins could lead to a lot more ways to end up being scammed.
Why? It's money.
BTCYou can walk away from a loan in fiat. Easy.
Lenders of fiat currency aren't protected from making bad investments by some sort of magic. They critique and analyze the data submitted by applicants for loans and verify their ID. This system would work for Bitcoin. It would work for any sort of cryptocurrency. It's just a payment method.