This is just an idea I had. If you can find a binary counter and ram chip that can be clocked at a high speed. (say 25-50mhz). You could make your own logic analyser. The idea is that the binary counter would count RAM addresses, and store a value from a ADC into the a new RAM cell each cycle. Then, after a certain amount of samples are taken, the clock would be stopped an some sort of MCU would read the data from RAM and send it to a PC. (The MCU would be able to read the ram at it's own rate, so you woundn't need a fast expensive MCU to actually take the samples real-time)