There's a big chance the VGA input of a flatscreen tv can also handle the 15khz signals as it is most likely the very same chip the EU SCART connectors are connected to.
Not here in North America there isn't.
I can't think of a single flatscreen TV that is sold here in the US that can take 15khz over VGA. Sure, there are some multisystem flatpanels that are sold by specialty stores, but they are stupid expensive as they are not mainstream. You can't wonder into a retail store and buy these...mostly just order over the 'Net. They are probably imported from the UK anyways.
However many of the inexpensive LCDs do sync to 50Hz PAL signals over composite/s-video or component. I own 2 Vizio sets that both do...a 26 inch and 47 inch. But if you buy a big name model - Sony, Toshiba, Panasonic and etc, there is just about ZERO percent chance they will sync to 50Hz sadly.