A one-off project?
You can add USB by plugging the video camera's RCA plug (often yellow) into a cheap USB video grabber dongle. Such dongles are about $50+ depending mostly on the video quality. They plug into your laptop or PC.
What's the memory for? Are you trying to make a camcorder with solid state memory? If so, then the cheapest solution by far is to purchase a cheap video camera ($200+ these days, maybe even less).
You can purchase small hidden security cameras that will record into internal memory for later downloading (often USB). Google "baby-sitter cams" and similar. I recently saw one that is a little golf-ball size device that records video into internal memory.
