Here at BTCjam we offer linked-loans which use reference currencies. Referenced currency means that you are effectively taking out a Bitcoin loan that is to be repaid in the amount borrowed as a local currency (plus interest)
If the price of 1 BTC is $1000 BRL and you borrow 10 BTC for 180 days, you will owe $10,000 BRL plus the interest, paid back over the 6 months, regardless of what the BTC price is. If the BTC price rises to $2,000 BRL right after you activate your listing, you will only owe the $10,000 BRL plus the interest. In this scenario you, as the borrower always owe the same amount of your local currency regardless of the price of bitcoin.