Our post about custom clothing company Construct led the T324 office to a discussion of personalized printing and on-demand custom product companies.
Store manager Brian remembered "back when I was a junior in high school" ordering "tons of stuff" from CafePress; your bloggess recalled Zazzle entering the field, with more refined products than CafePress, and their arms race for the sought-after black custom-printed t-shirt.
So we trotted over to Zazzle to see what else you can get custom-printed now, and it's not just t-shirts and mugs!
How about laptop bags and sleeves? I knew you could get a laptop skin, but the possibilities of sleeves are delightful!
The bags are spendy at $169.95, but made by SF hipster institution Rickshaw Bagworks and local, sustainable, blah, blah, blah.
Of course there's about a million (really pretty gorgeous) steampunk iphone case designs already uploaded, but you can totally upload your own. (Not enough laptop/Kindle/iPad case options? Try Brooklyn-to-Berlin hipster company caseable.)
Zazzle has aprons now; although the colors kind of suck, this T. Rex On A Bike motif looks pretty cute on the khaki. (Spreadshirt has better colors, including black, but they don't do pixel-based image prints on them, which is really the point, isn't it?)
And the t-shirts have some great options now; there's custom embroidery, with or without your own stitch file, that can ship in as little as 24 hours!
(The advent of home embroidery machines has created a whole other business, the selling of digital stitch files like these gorgeous ones at UrbanThreads.com!) There's far more t-shirt styles overall; I love this Wonder Woman t-shirt in a plus-size v-neck, licensed from my dear former employers, DC Comics, through their Zazzle partnership.
There's also official licensing for these entirely awesome Grumpy Cat playing cards.
Zazzle and Cafepress royalties are a great Web 2.0 passive income source for nice meme-jackpot folks like Grumpy Cat's owners, while it lasts. 
And a deck of custom-printed playing cards for $20 is ridiculously neat. Why haven't I been making these and giving them to everyone?
Over at Cafepress, they have flip flops! 
And shower curtains!
And a whole bunch of other new items since the last time I visited. There's flask necklaces (many Apocalypse designs already uploaded for your choice), stadium blankets and actual sheets and pillowcases, and a more affordable computer bag, shown here in user Desert Willows' Baby Hedgehog design.
We also love the way user Sciencephotos' computer circuit print looks on the small serving tray and glass cutting board! Sadly, we have no examples of what the quality of Cafepress printing is these days, on any of these surfaces.
It was while checking out the Home Office section that we discovered user "GettyImages".
With 106,691 products as of this writing, image licensing titan Getty has basically come up with a formula for using Cafepress to print money.
I searched on "Beyonce" to see if there were any unflattering images, but there were none of any kind yet. Is some poor Getty intern uploading images and creating products one at a time? Couldn't they just write some code for that?
We also clicked on "Underwear & Panties", a fashion vertical Zazzle wisely avoided, and discovered a users' race to the bottom that we'll spare you a link to.
What does all this personalization mean?
It means we are in the very early days of complete consumer control of product design. Why can't I print my own custom clothing at home every morning right now? Because we haven't solved the nano-manufacturing / Replicator / universal assembler problem yet. Be patient a little longer.
Meanwhile, read the totally fascinating Replicator Inc (tagline: "Putting the 'Custom' back in Customer") blog by Joseph Flaherty to stay up to date on the "the companies and products that combine the connectivity of the internet with the physicality of products", and check out Frank Piller's mass-customization.de.