Tired of mobile developer blues?
Try building your app for your ideal mobile device and then bundle it with the device and necessary connectivity. Then release a new version every 1-2 years to leverage latest advances in hardware.
Don't sell it to teenagers. Sell it to small business owners who need weapons to compete against the online onslaught. Read my handblogging post if you are short of ideas. Think barcodes, RFID tags, customization, availability, and relationships. Aggregate metadata collected by a national network of application-specific mobile devices.
If this trail of thought doesn't make you shiver, try farming.