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 $64 US. Gabotronics also sells the smaller XMEGA Protolab with similar features for $49.
Gabotronics is developing another oscilloscope with a larger analog bandwidth and sample rate, the AVR Xmegalab that will sell for $249. It isn't small enough to plug into a breadboard, but you can also use it for a development board for the ATXMEGA128A1 microcontroller. There is also the XMEGA Xminilab-B that is less powerful but available now for $150 and features the ATXMEGA32A4.