it is possible,
Code:
////
your html/JS code for feeding the RSS
////
<script language="javascript">
if(window.innerHeight>100){
//launch Qt app with Platform Services 1.0 AppManager API ( http://www.developer.nokia.com/Resources/Library/Web/web-apps/symbian-web-runtime/symbian-web-runtime-api-reference/platform-services-10-javascript-api-reference/platform-services-10-appmanager-api.html )
}
</script>
////
but how would you distribute your app? because are 2 different applications: one developed in WRT and one in Qt...