We had some weird thing going on while porting Listview over to the new QScroller:
Let's say you have QDeclarativeVisualDataModel vdm with 9 items and no delegate.

vdm->count() is 9 and that's ok (or not?)

now as soon as you set a delegate via QDeclarativeVisualDataModel::setDelegate(), you will get a itemsInserted() signal telling you that 9 items were inserted.
After that

vdm->count() is still 9 and that's weird now. We had 9, we got an insertion notification for another 9 and we still only have 9?

My guess is that something like this patch would make it a lot saner (0 items via count() as long as we don't have a delegate)

diff --git a/src/declarative/graphicsitems/qdeclarativevisualitemmodel.cpp b/src/declarative/graphicsitems/qdeclarativevisualitemmodel.cpp
index e569dd2..0199a6a 100644
--- a/src/declarative/graphicsitems/qdeclarativevisualitemmodel.cpp
+++ b/src/declarative/graphicsitems/qdeclarativevisualitemmodel.cpp
@@ -937,6 +937,8 @@ void QDeclarativeVisualDataModel::setPart(const QString &part)
 int QDeclarativeVisualDataModel::count() const
 {
     Q_D(const QDeclarativeVisualDataModel);
+    if (!d->m_delegate)
+        return 0;
     return d->modelCount();
 }