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.
I plan to have Silver ready (mine) to sell. I will only sell as many shares as I have silver in my pocket. This way I cannot end up owing more than I hold. Buyer will pay shipping to anywhere in the world, tracking optional but recommended.
Silver price will always fluctuate, but when it is low and people purchase it would be a good deal to sell it or withdraw and make some profit, without the fees that bullion dealers take when purchasing silver.
