It seems to me that it would be a reasonable challenge to take the "free" microsoft 'C' development tools and the drivers provided by, say, FTDI, and use the 'C' compiler to produce display software and one of the ubiquitous USB devices from that manufacturer to interface a device like a logic analyzer/oscilloscope based on a CPLD or FPGA, together with a couple of flash-converters in the case of the oscilloscope, and it should be quite straightforward producing a useable display.

I've produced that sort of thing under DOS, though it's been a while. The LA was just an event-trigered sampler, rather than one having complex triggering capability. I've built complex trigering circuits for logic analyzers using discrete logic and I've built small ones using an oscilloscope as a display. It's clearly possible.

As for the display, ... if you can build a simple CRT refresh memory, as one used with microcomputers back in the '70's, particularly with TV-type displays as was common practice back then, all you have to do is to sample to a RAM and substitute a task-specific character generator.

Being Windows-daunted, I've never attempted it ... <sigh> ... Maybe one of these days ...

RE