There are already a few ongoing and a few in planning stage so the idea has merit. One thing I would fear pegging things at 1oz your share cost is going to be one of the highest on GLBSE.  Your share value is going to be greater affected by changes in BTC price and silver price which could be discouraging to some investors but it could also be attractive to others. 

Provide a few more details on your planned model, I started writing a question list but it was just so large it isn't worth asking.