right now I'm at the start of my final semester project (I implement the USB Connection + GUI for a 'I compute the s**t out of you'-FPGA) and my boss who is designing the FPGA moaned about his "crappy" logic analyzer. The problem is the small memory, thus it can't record enough data. I experienced the same issue with several DSOs.
Problem is that ... those devices with mucho RAM cost the same like a small car, but who am I telling this? Well ... gosh why is this so? If you calculate todays memory prizes down to "$ per Bit" we pretty much get money back.
Plus: I'm eager to lean FPGA programming since about a year. Wouldn't this be a nice starter project? (keep in mind that I learn how to do USB streaming and GUI right now) I'm thinking about 32 Channels scanning a bus which runs with ... maybe 100 MHz? (whew, OK that would produce 400 MB raw data per second(!) )