You can rename widget title:
$subject = "RSS";

You can set number items per feed:
$feed->set_item_limit(5);

You can set multiple source:
$feed->set_feed_url(array(
	'http://newsrss.bbc.co.uk/rss/newsonline_world_edition/front_page/rss.xml',
	'http://rss.news.yahoo.com/rss/topstories',
	'http://news.google.com/?output=atom',
	'http://rss.slashdot.org/Slashdot/slashdot',
	'http://rss.cnn.com/rss/cnn_topstories.rss',
	'http://www.newsvine.com/_feeds/rss2/index'
));

Or Google News from your region:
https://news.google.com/rss/search?q=Dukovany+OR+EZ
https://news.google.com/rss/search?q=Dukovany+OR+EZ&hl=cs&gl=CZ&ceid=CZ:cs


More on http://simplepie.org/wiki/reference/simplepie/set_feed_url
