Gabotronics, a developer of tools for electronics hobbyists, has released a new larger size oscilloscope display that can be mounted on a solderless breadboard.
The XMEGA Minilab is not just a mixed signal oscilloscope - it also has a meter mode, spectrum analyzer and arbitrary waveform generator with frequency sweep. It has a micro USB connection but the interface is still under development. The logic analyzer has 8 digital inputs and can decode UART, I2C and SPI. The scope has 2 analog inputs with 200kHz bandwidth and 2MS/s maximum sample rate. You can buy it direct for $69 US. Gabotronics also sells the smaller XMEGA Protolab with similar features for $49.
UPDATE: Gabotronics has developed a few portable oscilloscopes and is developing an oscilloscope watch.