So I'm going to try my hand at some Volokh Conspiracy designs -- I'll probably pick a few that sound promising and provide them as options. Have it your way, that's our slogan here at The Volokh Conspiracy, though for intellectual property reasons we probably won't use that one on the T-shirts.
But the question: What service to use? I'd heard good things about CafePress, but then ran across some negative reviews (first in a comment on the Paraphernalia post, and then in some comments I found online). Zazzle sounds like an alternative, but I've only heard a little about them. I'm not looking for a place that will do the design; I'm planning on having something pretty simple, so I can do it myself. I'm looking for something that will take orders, create the goods, and ship them.
High-quality stuff, not cheapo iron-ons that will crack or peel after a few washings.
As low a price as possible, given constraint #1.
Good customer service for buyers.
Ease of use for me (so for instance having all the products on one service is better than splitting among two).
No or low cost for us.
Variety of products -- for instance, polo shirts as well as T-shirts, coffee mugs and mousepads as well as clothes, and the like.
Whatever else I'm forgetting, though that might have to be a higher priority.
Any suggestions? Please post them in the comments, since I think other readers might be looking for similar information, for their blogs, for their other projects, or just for something noncommercial for themselves and friends.