Relisys RLT1720. Widescreen TFT, combined TV and PC monitor.

I know what I'm doing, I'm not daft, and have been round the menus 100 times for good measure. It simply doesn't support that video mode. It works fine with PS2 games, which are clearly a different mode.

I'd venture a guess that it's some form of interlacing that this particular model of TFT can't handle properly (CRTs work by drawing one line at a time at a rapid rate. LCDs have to interperet this and display the whole screen in one go)