I'm sorry to say that I don't believe a TBC is an undertaking for an amateur. I was one of the inventors of the first digital TBC (US patent 3,860,952), and I don't believe they have been integrated to the point where you can just plop down a couple of chips. At minimum, you need two phaselocked loops, an A/D converter, a memory controller, and a memory, not to mention miscellaneous video amplifiers, sync separators, DC restorers, chroma separators, filters, a D/A converter if you want an analog output, etc. Perhaps you can find a used one on Ebay - but I don't know if any are available with digital output.
Ron