You don't find that many in domestic electronics, simply for price reasons - for a mass produced product it's cheaper to use a plain LCD and a micro-controller with an LCD interface internally.
Places I have seen them are fax machines and burglar alarm control panels, you might find them in older laser printers and copiers as well.
But they are not too expensive to buy, try any of the usual component suppliers - even Maplin stock them.
Surplus catalogs carry the ones with built-in controllers that you want, quite cheaply. You did not mention if you want graphics or just text-based. (I would not bother trying to do a numeric-segment display, the alphanumerics are easier to find and cheap).