Your challenge is any time in the modern era to have an election where both the presidential and vice presidential nominees of both parties all have the same first name.
Bonus points if you can inflict this on minor parties too.
2004:
D - John Kerry, John Edwards
R - John McCain, John Ellis ("Jeb") Bush
PoD: Clinton resigned in 1998 when his misbehavior was exposed; Gore finished Clinton's term and was re-elected in 2000. Gore could not seek a second full term in 2004, having served over six years.
Other possibilities:
1916 - two Charles (Hughes, Fairbanks)
1908 - two Williams (Taft, Bryan)
1900 - two Williams (McKinley, Bryan)
1896 - two Williams (McKinley, Bryan)
1856 - two Johns (Fremont, Breckinridge)