In Java at least this has been tried before. There was something called the Jaxx Framework . jaxxframework.org now seems to be defunct so I guess it died.
Personally I'm unenthused.
For one thing, the typical reason to write native apps these days is that it's a mobile app. Certainly on iOS you'd be better off staying on the reservation. There's only 2/3 resolutions to support anyway (plus two orientations for each). Android is of course more varied.
For desktop apps, you're getting increasingly specialized software (the rest going to Web apps) and your best bet is still to stick to the native libraries (Cocoa, WPF, etc).