I remember discussing this with you last year, Scott...
Cafepress is good as sort of an "instant solution," business-wise... for what they offer versus the depth of product, it's an okay substitute for real <i>manufactured</i> merchandise (such as Sandra's offering of BMB teeshirts).
It's not like I've never had the money to get a Cafepress PDI mug or t-shirt or hoodie, but I can't say there's anything on the site to remind me to do so except lately with the bunnies & such. I'm more interested in a coffee mug than a bunny, though.
Perhaps one of those quick-poll things you can set as a script on the main page to do a survey? The problem with going away from the Cafepress arena is that you'll be capitalising for inventory and that's really putting it out on the chopping block. then again, it could lead to profit...
as for printing, one-off prints from a kinko's laser are pretty spendy. You can likely get htem reproduced, poster-style in batches of 100 or 500 at a local printery, though that's a capital outlay, as well, what with 4-color or offset printing.
If you're looking for a few one-off goods, you can even offer something that you've done, yourself... silk-screening isn't too terribly tough, and it's a capital improvement instead of inventory, and you can control the quality as well as the unique nature of the merchandise (no 2 exactly alike!). The outlay will be significantly less than building up a 4-size inventory of shirts in any quantity, and you can better control inventory by only buying what you need or what's ordered.
For price-range, it's an easy answer: Under $20. $20 is affordable, and it'd keep the package under $25 with shipping & handling costs... (tyvek envelope + t-shirt = about 1 lb.)
i'm chock full of ideas (but nobody hires me for this shit. you're lucky i like you, i might start charging), and we can chat at length any time... =)
"If I had a nickel for ever time I've heard that, I'd fill a sock with them and beat the shit out of you for saying something so stupid."