Since the Dems are getting 3 days of coverage (since they only have 3 days), the GOP is also:
Ann Romney may not make prime time during next week's Republican National Convention.
The three major television networks — NBC, ABC and CBS — are not airing prime-time coverage of the RNC on Monday, the opening night of the convention and the night that Ann Romney has been scheduled to deliver the keynote address. So in order to get Mitt's wife onto television, the campaign may have to scramble and reschedule her speech.
Of course, the broadcast networks have been cutting back coverage for years now, and 3 nights of 1 hour coverage (maybe 2 on Thursday) has been the norm for a while.
Update: The networks did have 4 hours of each convention in 2008, driven by Obama/Clinton interest, and the need to match on the GOP side. But they did 3 hours each in 04.
Also, due to the NBC season-opening football game, NBC will not broadcast on Wednesday, but will broadcast an extra hour on Thursday.