A friend of mine was visiting us last week with their 2year old. And he sounds just like your 2 year old Melanie (and his name is Jack too lol). He dropped his day time sleeps as soon as he turned 2, he is so full of energy that no matter what they do to tire him out, he just doesn't stop. But if he's at daycare, or being babysat by someone else, he'll have day sleeps. What's worse for them, is every since they introduced the bed, he's stopped sleeping well at night. So both day and night are absolute nightmares for them.

They're still trying to find an answer, so I'll keep an eye on this thread and let them know the suggestions.