Here are some things that I'd like to see:
Ketchup/mustard, similar to the Goober brand peanut butter/jelly They would be in individual chambers, like Aquafresh toothpaste, depending on dispension the two could be made to twist beautifully, like a vinegar candy cane. (I heard that a Babysitters' Club book mentioned that a combined orange paste was a burger shak's "secret sauce.")
With all the current features (organizer, web browser, high color display, camera, etc.) packed into today's ultra-slim phones, I don't see why they can't make a feature-free (just phone) cell the size of a watch, pen, or multi-tool, for relatively cheap, Those disposable phones didn't take off, but a durable, small and simple one might be marketable
Carbonated tea, which is made, but not with a wide enough distribution.
Shoes with cleats that are recessed, like cat's claws. They would come out when toes were curled or with strong, sustained pressure caused by running via smart gel technology.
One thing I've wanted for a while was S'moreo cookies. Graham and marshmallow, with chocolate wedge. There are s'more type cookies now, but they suck.
Electronic bartender. I could put bottles of gin, vodka, rum, whiskey etc. in the back, hook it up to a soda fountain (CO2 pump, water line and syrup), and have the thing select from appropriate glasses or plastic glasses (or just whatever glass you put under the dispenser) and make the drink. Would need controlled delivery (tequila sunrise) and stirrer (could dispense stirrers and use them with simple servo, rubberized grip?) Would be expensive but awesome. Need an old laptop to program in drinks (maybe the user can customize strength and and new drinks). Spill-proof touch display. Muy awesome.
No robotic arm to worry about calibration. Moving parts: valves (have to research types), servo for stirring, grip for stirrers (optional), gate mechanisms for dispensing cups and or stirrers (optional).
Computing power: a scientific calculator could do it, but might want a graphical display, so I'd say old laptop and touch screen (market demo only).
I could write it in Visual Basic, or C++ (have to brush up), need robotics controller output via serial port or USB
This would be fantastically simple.
Little square box with cutsey labeling. Simple record and playback chip and battery (like those kid keychain things for $3 where you push button and then can warp playback). Opening box triggers record function for ten seconds. Close the box quickly. Open it and it plays back last recording, but only once. Hallmark would love it. Put a ring inside, ask for marriage...
Debit cards that have a simple LED display that shows balance. This would be easy. Squeeze the edges to activate to save battery life. Solar powered even. Only stumbling block: data transfer from existing ATM's. Account information (e.g. balance) isn't stored locally, so I'm not sure how this would work.
Automatic hemming of clothes. Micro zippers, with rows of teeth arranged in parallel lines, could do it. Have no idea if this is sensible.
A combination washer/dryer. I hoped to god that they had these already. I don't see what the big problem would be, other than water drainage. Front load washer, high-velocity spin to get out most of the water, then tumble dry with heat. What is the problem? They have them, specifically for limited space apartments and condos. Unfortunately they are prone to malfunction. DAMN.
Quote from Autumn #1: "It tickles when you put things in my butt!"
(When I warned her I would take this out of context and post it here she replied with quote #2).
Quote from Autumn #2: "I'll just tell them that Mom likes to put pencils in my butt."
I love my girlfriend.