Logan2010

http://daytimeroyaltyonline.com/single/?p=8489105&t=8457303

GENERAL HOSPITAL
Ted King - Luis Alcazar (2002) and Lorenzo Alcazar (2003-2007)
Natalia Livingston - Emily Quartermaine (2003-2008) and Rebecca Shaw (2009)

Casey

http://daytimeroyaltyonline.com/single/?p=8489312&t=8457303

Days: Eileen Davidson: Kristen Blake- Susan Banks- Thomas- Penelope- Sister Moira

Titus Andronicus

http://daytimeroyaltyonline.com/single/?p=8489854&t=8457303

Dee and Andrea Hall both did scenes as Samantha Evans and Hattie Adams.
If you want to count lookalikes:
Bill Hayes as Doug Williams and Byron Carmichael
Thaao Penghlis as Andre and Tony DiMera
Charles Shaughnessy as Shane and Drew Donovan
Robert Kelker-Kelly as Bo Brady and Mitch

blueskies

http://daytimeroyaltyonline.com/single/?p=8490027&t=8457303

^ not to mention Kristian Alfonso as Hope Williams Brady & Gina Von Amberg