As of the moment, it appears that physical supply of 100oz silver is drying up.
Tulving.com, one of the largest dealers, says they are sold out:
http://tulving.com/goldbull.html
apmex.com shows less that 1,000 bars in inventory:
http://www.apmex.com/Category/1193/100_oz_Silver_Bars.aspx
provident.com is also sold out:
http://www.providentmetals.com/bullion/silver/private-slv/100-ozt-bar.html
Tulving.com, one of the largest dealers, says they are sold out:
http://tulving.com/goldbull.html
apmex.com shows less that 1,000 bars in inventory:
http://www.apmex.com/Category/1193/100_oz_Silver_Bars.aspx
provident.com is also sold out:
http://www.providentmetals.com/bullion/silver/private-slv/100-ozt-bar.html