Bryan, it looks like you got your money's worth from the one on top. Nice to see it working
Ian, looks ike a close one between XL-100 and Colortrak. The first XL-100s were released in 1971, but I can't find anything, even on RCA's site, that indicates when the last ones were made. Looks like it's only been a couple of years. The first Colortrak came out in about 1977 and RCA still has one in production - a little 13-incher.