I've gone through and deleted everything except T-shirts from my Zazzle store. I've had multiple complaints about the quality of the printing an non-apparel items like the mugs, so I'm searching for a more reliable provider for those items. From looking at a couple of Zazzle-oriented forums it appears my concerns aren't isolated.
On the other hand, I've expanded the number of T-shirt designs by adding distressed versions of both the Australian and Antarctic Miskatonic expedition logos. I think the increased tonal range of the worn design looks better on the large canvas available on a T-shirt.
Update: Woot! The distressed Australian Expedition Logo T-shirt is a "Featured Product" on the Zazzle homepage. My pathetic ego is most pleased.