class Circle
{
    public double X {get;set;}
    public double Y {get;set;}
    public double Diameter {get;set;}
    public static double Height {get;set;}
    public static double Width {get;set;}
}

<ControlTemplate TargetType="{x:Type ListBoxItem}">
	<Canvas x:Name="canvas">
		<Canvas.Resources>
			<conv:TranslateConverter x:Key="TranslateConverter" />
		</Canvas.Resources>

		<Ellipse
			Width="{Binding Diameter}"
			Height="{Binding Diameter}"
			Stroke="Azure"
			Fill="Transparent"
			StrokeThickness="2"
		>
			<Canvas.Left>
				<MultiBinding Converter="{StaticResource TranslateConverter}">
					<Binding ElementName="canvas" Path="ActualWidth" />
					<Binding Path="Width" />
					<Binding Path="Diameter" />
					<Binding Path="X" />
				</MultiBinding>
			</Canvas.Left>

			<Canvas.Top>
				<MultiBinding Converter="{StaticResource TranslateConverter}">
					<Binding ElementName="canvas" Path="ActualHeight" />
					<Binding Path="Height" />
					<Binding Path="Diameter" />
					<Binding Path="Y" />
				</MultiBinding>
			</Canvas.Top>
		</Ellipse>		
	</Canvas>
</ControlTemplate>