Yes! I have just purchased another 200oz from the Perth Mint as a certificate. As a matter of general interest their selling price is $16.10 Aud per oz for this amount on a certificate (unallocated silver). Their buy back price is currently $15.46 Aud which equates to roughly 4% commission. Only just okay but I do not know of any other place that deals more cheaply.
I am not advocating purchase at this time - it might be good or it might not be. The only reason that I have bought is that it does not affect my average cost very much at all.