I doubt any broker would let a retail client accept or deliver on a commodity contract for many reasons, the main being it's odds on they won't have a deal setup with an official warehouse (all deliveries have to be made to an official warehouse). And an official warehouse probably won't want to deal with a small time client.
If you want a large amount of Silver, your best bet would be to work out a deal with a physical Silver dealer to accept delivery on your behalf, everything of course paid up front. They'll no doubt add a fee but it will probably be fair. If not, try another.
Where you're located and where the Silver will be delivered is something else to consider in that you might be in Denver and the Silver is delivered to NY. I think I'm right in saying that the deliverer chooses the warehouse to deliver to.