High Def TV is what we're all talking about now but I realised that the first HD job I was involved with was ten years ago - a Japanese opera shot using Sony's HDD1000 1" digital format - 1045 lines! See a pic of one here - looked like a BVH3000 as I recall. I think they were the first ones in Europe and we had a couple of Sony staff engineers looking after them - pictures were superb (uncompressed, I believe). Anyhow - I knew Sony had an analogue RGB HD format in the mid-eighties (30Mhz of bandwidth on 1" tape!) - in fact Bosch and Toshiba had similair machines to service the broadcast HD channels in Japan. You can see an excellent overiview here. There was also an early stab at D-Cinema in the form of the Proscan 290 - it recorded 10Mhz of analogue luma on 1" tape with the chroma being MPEG-1 encoded and multiplex'ed with the audio - here is the explanation nicked from Lion Lamb:

This machine is designed for a more subtle version of HD cinema (Compared to earlier attempts!) The luma (Main bulk of data) is stored using analog methods on FM carriers. There is no color burst or color subcarrier, so the resulting image is 'cleaner'. The analog information is digitally time- aligned, ensuring it lines up perfect with previous and future fields. The chroma channel uses MPEG style compression. On playback, the chroma and luma channels are carefully digitally time-aligned to eliminate problems with chroma jittering in relation to luma. The data rate of the chroma alone is about 3 Mbps. Seperate heads are apparently used for luma, and chroma/audio. There is spectrum left in the chroma and audio channels for a substantial amount of metadata. The format has not been popular at this time.