Another way of doing this is to enter into a contract where you voluntarily give away temporarily your owner and active authority to whoever is lending you the liquid Steem. To mitigate risk the recovery account would also need to be changed.
This does not require a hardfork but just building an application that already takes advantage of the functionalities of the blockchain.
Actually I'm writing out a post about this as a type of market idea... ill share it tomorrow, since I'm trying to space these ideas out... ;)