Locking up Bitcoin for BitUSD

[bitcrab]

this is a senseful topic, hope experts can advise.

[TravelsAsia]

Would it be possible to lock-up Bitcoin or Ether as collateral to create BitUSD? Attracting large communities with useful features seems like a nice win.  As a more out there question, would it be possible to transmit Bitcoin over the Bitshares network so it could take advantage of the 3 second transfer times (something to do with autobuy/sell BitBTC)?