MILAN, Feb 25 (Reuters) - Telecom Italia (TLIT.MI), opens new tab is exploring the introduction of premium- priced on-demand mobile services for customers seeking guaranteed fast and stable connectivity during large gatherings such as major sports events, its boss said on Wednesday. Italy remains one of Europe's most competitive mobile markets, with some operators offering 100-gigabyte monthly plans for under 10 euros ($11.78). Sign up here. "If you go to the stadium, you pay more for a coffee and for food ...