from UDE's Judge Certification Program (YGO)
Q:
If I take control of my opponent's monster with "Mark of the Rose", and afterwards I activate "Giant Trunade", who gets control of the monster?
A:
If you equip your opponent's monster with "Mark of the Rose", when "Mark of the Rose" is removed from the field, control of the equipped monster returns to your opponent. If your opponent already has control of the monster, it remains on their side of the field.
http://entertainment.upperdeck.com/community/forums/thread/1561761.aspx
Q:
If I take control of my opponent's monster with "Mark of the Rose", and afterwards I activate "Giant Trunade", who gets control of the monster?
A:
If you equip your opponent's monster with "Mark of the Rose", when "Mark of the Rose" is removed from the field, control of the equipped monster returns to your opponent. If your opponent already has control of the monster, it remains on their side of the field.
http://entertainment.upperdeck.com/community/forums/thread/1561761.aspx