I've seen low-cost development boards based on a Cypress CY7C68013 (FX2) which can be used as a logic analyser, but how about using these boards as a logic generator (with a continuous streaming function which makes use of the FIFO - can also be used as a waveform generator up to (in theory) 48 MHz @ 8 bit output/24 MHz @ 16 bit output - possibly only an X^2 fraction of that) and even as a high speed Bus Pirate?
The Cypress FX2 has the ability to load "soft" firmware over USB via a vendor-defined command in the I2C EEPROM.
Also, I've read the Hantek 6022BL (based on an FX2) samples at 48 MS/s (one analog channel; half for both channels) and the 16 bit logic analyser operates at up to 24 MHz; therefore, the 6022BL most likely has a continuous streaming function.