AFAIK, the MAKER project on ethereum plan to issue stable currency with BTC as collateral, how can they do this? is the same way possible on Bitshares?
and in NXT there are also MULTIGATEWAY that bridge BTC and NXT platform, which makes the BTC in NXT close to real BTC, any thing can be learned from?
one problem in Bitshares is how to supply enough smartcoin, if BTC can be introduced as collateral, things will be much better.